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Practice › LeetCode › LeetCode 36xx ›

LeetCode 3628 - Maximum Number of Subsequences After One Inserting

LeetCode Problem 3628 Difficulty: 🟡 Medium Topics: String, Dynamic Programming, Greedy, Prefix Sum Solution Problem Understanding We are given a string $s$ consisting of uppercase English letters. From this string, we are interested in counting subsequences equal to the pattern "LCT" , where a subsequence means indices $i < j < k$ such that $s[i] = \text{L}$, $s[j] = \text{C}$, and $s[k] = \text{T}$. We are allowed to insert at...

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LeetCode 3883 - Count Non Decreasing Arrays With Given Digit Sums

LeetCode Problem 3883 Difficulty: 🔴 Hard Topics: Array, Dynamic Programming, Prefix Sum Solution Problem Understanding The problem asks us to compute the number of non-decreasing arrays of integers where each integer satisfies a specific digit sum constraint. Specifically, we are given an array digitSum of length n , where digitSum[i] represents the required sum of digits for the i -th element in the array. We must construct arrays arr of...

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LeetCode 3788 - Maximum Score of a Split

LeetCode Problem 3788 Difficulty: 🟡 Medium Topics: Array, Prefix Sum Solution Problem Understanding The problem asks us to maximize a "score" obtained by splitting an integer array nums at a valid index i . For each split index i , the score is calculated as the sum of all elements from the beginning of the array up to i ( prefixSum ) minus the minimum value in the remaining elements...

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LeetCode 3864 - Minimum Cost to Partition a Binary String

LeetCode Problem 3864 Difficulty: 🔴 Hard Topics: String, Divide and Conquer, Prefix Sum Solution LeetCode 3864 - Minimum Cost to Partition a Binary String Problem Understanding We are given a binary string s , where each character represents whether an element is sensitive: '1' means the element is sensitive. '0' means the element is not sensitive. The entire string initially forms one segment. Every segment has a storage cost that...

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LeetCode 3862 - Find the Smallest Balanced Index

LeetCode Problem 3862 Difficulty: 🟡 Medium Topics: Array, Prefix Sum Solution LeetCode 3862 - Find the Smallest Balanced Index Problem Understanding We are given an integer array nums , and we need to find the smallest index i that satisfies a special balance condition. For a given index i : The left sum is the sum of all elements strictly before i , that is, nums[0] + nums[1] + ......

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LeetCode 3771 - Total Score of Dungeon Runs

LeetCode Problem 3771 Difficulty: 🟡 Medium Topics: Array, Binary Search, Prefix Sum Solution Problem Understanding The problem describes a dungeon with n rooms, where entering room i reduces your health points by damage[i] . After taking this damage, if your remaining health is at least requirement[i] , you earn 1 point for that room. You can start your dungeon run at any room j (1-indexed) and proceed through the rest...

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LeetCode 3756 - Concatenate Non-Zero Digits and Multiply by Sum II

LeetCode Problem 3756 Difficulty: 🟡 Medium Topics: Math, String, Prefix Sum Solution Please provide the official LeetCode problem statement or confirm the exact problem details for LeetCode 3756 - Concatenate Non-Zero Digits and Multiply by Sum II . I want to avoid hallucinating the intended optimal approach because this appears to be a very recent/problem-specific question, and correctness matters for the full guide, code, worked examples, and complexity analysis. The...

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LeetCode 3845 - Maximum Subarray XOR with Bounded Range

LeetCode Problem 3845 Difficulty: 🔴 Hard Topics: Array, Bit Manipulation, Trie, Queue, Sliding Window, Prefix Sum, Monotonic Queue Solution Problem Understanding The problem asks us to find a subarray of a given non-negative integer array nums such that the difference between the maximum and minimum elements of the subarray does not exceed a given integer k . Once such a subarray is chosen, we compute the XOR of all its...

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LeetCode 3826 - Minimum Partition Score

LeetCode Problem 3826 Difficulty: 🔴 Hard Topics: Array, Divide and Conquer, Dynamic Programming, Queue, Prefix Sum, Monotonic Queue Solution LeetCode 3826 - Minimum Partition Score Problem Understanding We are given an array nums and must divide it into exactly k contiguous subarrays. For every subarray, we first compute its sum: $$\text{sumArr} = \sum \text{elements in the subarray}$$ Its value is then defined as: $$\text{value} = \frac{\text{sumArr} \cdot (\text{sumArr}+1)}{2}$$ The score...

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LeetCode 3739 - Count Subarrays With Majority Element II

LeetCode Problem 3739 Difficulty: 🔴 Hard Topics: Array, Hash Table, Divide and Conquer, Segment Tree, Merge Sort, Prefix Sum Solution Here’s a complete, detailed technical solution guide for LeetCode 3739 - Count Subarrays With Majority Element II following your requested format. Problem Understanding The problem asks us to count the number of contiguous subarrays in which a given target element is the majority element . A majority element is one...

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LeetCode 3737 - Count Subarrays With Majority Element I

LeetCode Problem 3737 Difficulty: 🟡 Medium Topics: Array, Hash Table, Divide and Conquer, Segment Tree, Merge Sort, Counting, Prefix Sum Solution Here is a comprehensive, detailed reference guide for LeetCode 3737 - Count Subarrays With Majority Element I , following your formatting requirements exactly. Problem Understanding The problem provides an integer array nums and a target integer. The goal is to count the number of subarrays in which the target...

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LeetCode 3728 - Stable Subarrays With Equal Boundary and Interior Sum

LeetCode Problem 3728 Difficulty: 🟡 Medium Topics: Array, Hash Table, Prefix Sum Solution Problem Understanding The problem asks us to count stable subarrays in an integer array capacity . A subarray capacity[l..r] is stable if it satisfies two conditions: its length is at least 3, and the first and last elements are each equal to the sum of the elements strictly between them. In other words, for a subarray [a0,...

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LeetCode 3721 - Longest Balanced Subarray II

LeetCode Problem 3721 Difficulty: 🔴 Hard Topics: Array, Hash Table, Divide and Conquer, Segment Tree, Prefix Sum Solution Problem Understanding The problem requires us to find the length of the longest subarray in an integer array nums where the count of distinct even numbers equals the count of distinct odd numbers . A subarray is a contiguous section of the array, and “distinct” means that duplicate values are counted only...

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LeetCode 3714 - Longest Balanced Substring II

LeetCode Problem 3714 Difficulty: 🟡 Medium Topics: Hash Table, String, Prefix Sum Solution Problem Understanding The problem gives us a string s that contains only three possible characters: 'a' , 'b' , and 'c' . We must find the longest substring where every distinct character in that substring appears the same number of times . A key detail is that the condition only applies to distinct characters present in the...

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LeetCode 3709 - Design Exam Scores Tracker

LeetCode Problem 3709 Difficulty: 🟡 Medium Topics: Array, Binary Search, Design, Prefix Sum Solution Problem Understanding This problem asks us to design a system that tracks Alice's exam scores over time and efficiently computes the total score for any given time interval. The system must support two operations: recording a new exam with a timestamp and score, and querying the total score of exams between two timestamps inclusive. The input...

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LeetCode 3699 - Number of ZigZag Arrays I

LeetCode Problem 3699 Difficulty: 🔴 Hard Topics: Dynamic Programming, Prefix Sum Solution Here is the complete technical solution guide for LeetCode 3699 - Number of ZigZag Arrays I , formatted exactly according to your specifications. Problem Understanding The problem asks us to count arrays of length n where each element is within the range [l, r] and satisfies the ZigZag constraints. A ZigZag array has two main rules: no two...

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LeetCode 3698 - Split Array With Minimum Difference

LeetCode Problem 3698 Difficulty: 🟡 Medium Topics: Array, Prefix Sum Solution I can write the full detailed guide, but I need to flag one issue first: the problem statement for LeetCode 3698 - Split Array With Minimum Difference appears inconsistent with the provided Go stub and the current LeetCode catalog. Before I produce a rigorous reference-quality solution, I need to confirm the exact problem definition, because there is a high...

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LeetCode 3755 - Find Maximum Balanced XOR Subarray Length

LeetCode Problem 3755 Difficulty: 🟡 Medium Topics: Array, Hash Table, Bit Manipulation, Prefix Sum Solution LeetCode 3755 - Find Maximum Balanced XOR Subarray Length Problem Understanding This problem asks us to find the longest contiguous subarray that simultaneously satisfies two independent conditions: The bitwise XOR of all elements in the subarray is equal to 0 . The subarray contains an equal number of even and odd elements. We are given...

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LeetCode 3729 - Count Distinct Subarrays Divisible by K in Sorted Array

LeetCode Problem 3729 Difficulty: 🔴 Hard Topics: Array, Hash Table, Prefix Sum Solution Problem Understanding The problem asks us to find the number of distinct subarrays in a sorted array nums such that the sum of elements in the subarray is divisible by a given integer k . A subarray is a contiguous segment of the original array, and two subarrays are considered distinct if their sequences of values differ,...

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LeetCode 3654 - Minimum Sum After Divisible Sum Deletions

LeetCode Problem 3654 Difficulty: 🟡 Medium Topics: Array, Hash Table, Dynamic Programming, Prefix Sum Solution LeetCode 3654 - Minimum Sum After Divisible Sum Deletions Problem Understanding This problem gives us an array nums containing positive integers and an integer k . We may repeatedly remove any contiguous subarray whose sum is divisible by k . After each removal, the remaining elements close the gap, meaning the array becomes shorter and...

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LeetCode 3548 - Equal Sum Grid Partition II

LeetCode Problem 3548 Difficulty: 🔴 Hard Topics: Array, Hash Table, Matrix, Enumeration, Prefix Sum Solution Problem Understanding The problem asks us to determine if we can partition a given m x n grid of positive integers into two connected sections by making exactly one horizontal or vertical cut , such that the sums of the two sections are equal or can be made equal by removing at most one cell....

Practice › LeetCode › LeetCode 34xx ›

LeetCode 3445 - Maximum Difference Between Even and Odd Frequency II

LeetCode Problem 3445 Difficulty: 🔴 Hard Topics: String, Sliding Window, Enumeration, Prefix Sum Solution LeetCode 3445 - Maximum Difference Between Even and Odd Frequency II Problem Understanding We are given a string s consisting only of digits '0' through '4' , and an integer k . For any substring subs whose length is at least k , we may choose two characters: Character a must appear an odd number of...

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LeetCode 3748 - Count Stable Subarrays

LeetCode Problem 3748 Difficulty: 🔴 Hard Topics: Array, Binary Search, Prefix Sum Solution Problem Understanding The problem asks us to count "stable" subarrays within a given array nums . A subarray is stable if it contains no inversions , which means that for any two indices i < j in the subarray, nums[i] <= nums[j] . Essentially, a stable subarray is non-decreasing . We are given multiple queries [li, ri]...

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LeetCode 3707 - Equal Score Substrings

LeetCode Problem 3707 Difficulty: 🟢 Easy Topics: String, Prefix Sum Solution Problem Understanding The problem asks us to determine if a given string s can be split into two non-empty substrings such that the sum of the alphabetic positions of characters in the left substring is equal to the sum in the right substring. Each character 'a' to 'z' maps to values 1 through 26 respectively. The input is a...

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LeetCode 3694 - Distinct Points Reachable After Substring Removal

LeetCode Problem 3694 Difficulty: 🟡 Medium Topics: Hash Table, String, Sliding Window, Prefix Sum Solution LeetCode 3694 - Distinct Points Reachable After Substring Removal Problem Understanding We are given a movement string s consisting of the four directions: U increases the y-coordinate by 1. D decreases the y-coordinate by 1. L decreases the x-coordinate by 1. R increases the x-coordinate by 1. Starting from (0, 0) , the entire string...

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LeetCode 3652 - Best Time to Buy and Sell Stock using Strategy

LeetCode Problem 3652 Difficulty: 🟡 Medium Topics: Array, Sliding Window, Prefix Sum Solution Problem Understanding This problem asks us to calculate the maximum possible profit from a stock trading strategy with the option to modify it once in a very specific way. You are given two arrays: prices , which contains the stock price on each day, and strategy , which tells you what action to take each day: -1...

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LeetCode 3636 - Threshold Majority Queries

LeetCode Problem 3636 Difficulty: 🔴 Hard Topics: Array, Hash Table, Binary Search, Divide and Conquer, Counting, Prefix Sum Solution Problem Understanding The problem asks us to process multiple queries on a given array nums where each query specifies a subarray defined by [li, ri] and a threshold . For each query, we need to find an element in the subarray that appears at least threshold times. If multiple elements meet...

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LeetCode 3632 - Subarrays with XOR at Least K

LeetCode Problem 3632 Difficulty: 🔴 Hard Topics: Array, Bit Manipulation, Trie, Prefix Sum Solution Problem Understanding This problem asks us to count the number of contiguous subarrays of a given array nums such that the bitwise XOR of all elements in the subarray is greater than or equal to a given integer k . The input array nums consists of positive integers, and k is a non-negative integer. A contiguous...

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LeetCode 3599 - Partition Array to Minimize XOR

LeetCode Problem 3599 Difficulty: 🟡 Medium Topics: Array, Dynamic Programming, Bit Manipulation, Prefix Sum Solution Problem Understanding This problem asks us to partition an array of integers, nums , into exactly k non-empty contiguous subarrays, and then compute the bitwise XOR of each subarray. The goal is to minimize the maximum XOR among these subarrays. Essentially, we are trying to distribute the elements into k groups such that the "largest...

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LeetCode 3578 - Count Partitions With Max-Min Difference at Most K

LeetCode Problem 3578 Difficulty: 🟡 Medium Topics: Array, Dynamic Programming, Queue, Sliding Window, Prefix Sum, Monotonic Queue Solution LeetCode 3578 - Count Partitions With Max-Min Difference at Most K Problem Understanding We are given an array nums and an integer k . We want to split the array into one or more contiguous, non-empty segments. Every element must belong to exactly one segment, and the segments must preserve the original...

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LeetCode 3546 - Equal Sum Grid Partition I

LeetCode Problem 3546 Difficulty: 🟡 Medium Topics: Array, Matrix, Enumeration, Prefix Sum Solution LeetCode 3546 - Equal Sum Grid Partition I Problem Understanding This problem asks us to determine whether a rectangular grid of positive integers can be split into two parts with exactly the same sum using a single straight cut. The cut can be made in only one of two ways: A horizontal cut between two adjacent rows....

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LeetCode 3540 - Minimum Time to Visit All Houses

LeetCode Problem 3540 Difficulty: 🟡 Medium Topics: Array, Prefix Sum Solution LeetCode 3540 - Minimum Time to Visit All Houses Problem Understanding This problem describes a set of n houses arranged in a circle. Between adjacent houses, there are two directed road systems: forward[i] is the distance from house i to (i + 1) % n . backward[i] is the distance from house i to (i - 1 + n)...

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LeetCode 3538 - Merge Operations for Minimum Travel Time

LeetCode Problem 3538 Difficulty: 🔴 Hard Topics: Array, Dynamic Programming, Prefix Sum Solution Problem Understanding This problem presents a road of length l kilometers, segmented by n signs at strictly increasing positions, where the first sign is at the start of the road ( position[0] = 0 ) and the last sign is at the end of the road ( position[n-1] = l ). Each segment between consecutive signs has...

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LeetCode 3511 - Make a Positive Array

LeetCode Problem 3511 Difficulty: 🟡 Medium Topics: Array, Greedy, Prefix Sum Solution Before diving into the detailed solution guide, I want to clarify one subtle point: the problem specifies that all subarrays with more than two elements must have a positive sum. This means the smallest subarray we need to consider is of length 3. This nuance is crucial for correctness. Here’s the comprehensive solution guide following your formatting rules....

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LeetCode 3500 - Minimum Cost to Divide Array Into Subarrays

LeetCode Problem 3500 Difficulty: 🔴 Hard Topics: Array, Dynamic Programming, Prefix Sum Solution Problem Understanding This problem asks us to partition an array nums into contiguous subarrays, where each subarray contributes a weighted cost to the total. The cost for a subarray nums[l..r] depends on two components: the sum of the elements in the subarray, adjusted by a factor k multiplied by the order of the subarray, and the sum...

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LeetCode 3494 - Find the Minimum Amount of Time to Brew Potions

LeetCode Problem 3494 Difficulty: 🟡 Medium Topics: Array, Simulation, Prefix Sum Solution Problem Understanding The problem asks us to simulate a sequential brewing process for potions performed by a series of wizards. Each wizard has a skill level that determines the speed at which they brew a potion, while each potion has a mana requirement that affects how long it takes to brew. Specifically, the time for wizard i to...

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LeetCode 3486 - Longest Special Path II

LeetCode Problem 3486 Difficulty: 🔴 Hard Topics: Array, Hash Table, Tree, Depth-First Search, Prefix Sum Solution LeetCode 3486 - Longest Special Path II Problem Understanding We are given a rooted tree with n nodes. The tree is rooted at node 0 , and every edge has a positive length. Each node also contains a value stored in the array nums . A path is considered special if it satisfies two...

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LeetCode 3480 - Maximize Subarrays After Removing One Conflicting Pair

LeetCode Problem 3480 Difficulty: 🔴 Hard Topics: Array, Segment Tree, Enumeration, Prefix Sum Solution Here’s a detailed technical solution guide following your requested format for LeetCode 3480 - Maximize Subarrays After Removing One Conflicting Pair . Problem Understanding The problem gives you an integer n , which defines a sorted array nums = [1, 2, ..., n] . You are also given a list of conflictingPairs , each representing two...

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LeetCode 3427 - Sum of Variable Length Subarrays

LeetCode Problem 3427 Difficulty: 🟢 Easy Topics: Array, Prefix Sum Solution Problem Understanding The problem provides an integer array nums of length n . For each index i , we are asked to consider a subarray that ends at i but starts at start = max(0, i - nums[i]) . This effectively means the subarray has a variable length depending on the value of nums[i] but never extends beyond the...

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LeetCode 3425 - Longest Special Path

LeetCode Problem 3425 Difficulty: 🔴 Hard Topics: Array, Hash Table, Tree, Depth-First Search, Prefix Sum Solution Problem Understanding This problem provides an undirected tree rooted at node 0 with n nodes and weighted edges, where each node has a value defined in the array nums . A special path is a downward path (from ancestor to descendant) such that all node values along the path are unique . The path...

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LeetCode 3413 - Maximum Coins From K Consecutive Bags

LeetCode Problem 3413 Difficulty: 🟡 Medium Topics: Array, Binary Search, Greedy, Sliding Window, Sorting, Prefix Sum Solution LeetCode 3413 - Maximum Coins From K Consecutive Bags Problem Understanding We are given several non-overlapping segments on a number line. Each segment [l, r, c] means that every bag at positions l, l+1, ..., r contains exactly c coins. All positions not covered by any segment contain 0 coins. The goal is...

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LeetCode 3333 - Find the Original Typed String II

LeetCode Problem 3333 Difficulty: 🔴 Hard Topics: String, Dynamic Programming, Prefix Sum Solution Problem Understanding The problem asks us to determine the number of possible original strings that Alice could have intended to type, given a string word that represents the final output and an integer k representing the minimum length of the original string. Because Alice may press keys too long, each character in the output may correspond to...

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LeetCode 3224 - Minimum Array Changes to Make Differences Equal

LeetCode Problem 3224 Difficulty: 🟡 Medium Topics: Array, Hash Table, Prefix Sum Solution Problem Understanding The problem gives us an integer array nums of even length n and an integer k . We are allowed to change any element in nums to any integer in the range [0, k] . Our goal is to ensure that for all symmetric pairs (nums[i], nums[n - i - 1]) , the absolute difference...

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LeetCode 3432 - Count Partitions with Even Sum Difference

LeetCode Problem 3432 Difficulty: 🟢 Easy Topics: Array, Math, Prefix Sum Solution Problem Understanding The problem gives us an integer array nums and asks us to count how many valid partition points produce an even difference between the sum of the left part and the sum of the right part. A partition is created by choosing an index i such that: The left subarray is nums[0:i+1] The right subarray is...

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LeetCode 3191 - Minimum Operations to Make Binary Array Elements Equal to One I

LeetCode Problem 3191 Difficulty: 🟡 Medium Topics: Array, Bit Manipulation, Queue, Sliding Window, Prefix Sum Solution Problem Understanding We are given a binary array nums consisting only of 0s and 1s. We are allowed to perform an operation any number of times: choose any three consecutive elements and flip them, meaning 0 becomes 1 and 1 becomes 0. The goal is to determine the minimum number of such operations required...

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LeetCode 2968 - Apply Operations to Maximize Frequency Score

LeetCode Problem 2968 Difficulty: 🔴 Hard Topics: Array, Binary Search, Sliding Window, Sorting, Prefix Sum Solution LeetCode 2968 - Apply Operations to Maximize Frequency Score Problem Understanding This problem asks us to maximize the frequency of the most common value in an array after performing at most k operations. Each operation allows us to choose any element and either increase or decrease it by exactly 1 . Since we can...

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LeetCode 2848 - Points That Intersect With Cars

LeetCode Problem 2848 Difficulty: 🟢 Easy Topics: Array, Hash Table, Prefix Sum Solution Problem Understanding The problem asks us to determine how many integer points on a number line are covered by at least one car. Each car is represented as a range [starti, endi] of integers, inclusive. For example, a car [3,6] covers the points 3, 4, 5, and 6. The input nums is a 2D array of these...

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LeetCode 2237 - Count Positions on Street With Required Brightness

LeetCode Problem 2237 Difficulty: 🟡 Medium Topics: Array, Prefix Sum Solution Problem Understanding The problem describes a street represented by positions from 0 to n - 1 . There are multiple street lamps, each defined by its position and range. A lamp at position p with range r illuminates all positions from max(0, p - r) to min(n - 1, p + r) , inclusive. The brightness of a position...

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LeetCode 2083 - Substrings That Begin and End With the Same Letter

LeetCode Problem 2083 Difficulty: 🟡 Medium Topics: Hash Table, Math, String, Counting, Prefix Sum Solution Problem Understanding The problem asks us to count all substrings in a given string s that start and end with the same character. A substring is a contiguous sequence of characters, so the order and adjacency of characters matter. The input s is a non-empty string consisting of lowercase English letters only, and its length...

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LeetCode 3354 - Make Array Elements Equal to Zero

LeetCode Problem 3354 Difficulty: 🟢 Easy Topics: Array, Simulation, Prefix Sum Solution Problem Understanding The problem gives us an integer array nums , where some elements may already be zero and others are positive integers. We must choose a starting index curr such that nums[curr] == 0 , and also choose an initial movement direction, either left or right. Once the process begins, we repeatedly follow a set of movement...

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LeetCode 2731 - Movement of Robots

LeetCode Problem 2731 Difficulty: 🟡 Medium Topics: Array, Brainteaser, Sorting, Prefix Sum Solution LeetCode 2731 - Movement of Robots Problem Understanding The problem gives us a list of robots positioned on an infinite number line. Each robot starts at a unique coordinate from the array nums , and each robot has an associated movement direction from the string s . A robot moves exactly one unit per second. If the...

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LeetCode 2428 - Maximum Sum of an Hourglass

LeetCode Problem 2428 Difficulty: 🟡 Medium Topics: Array, Matrix, Prefix Sum Solution Problem Understanding The problem provides an m x n integer matrix grid and asks for the maximum sum of an hourglass shape within the matrix. An hourglass is defined as a 3x3 structure with the top and bottom rows fully included, and only the center element from the middle row. Specifically, if i and j denote the top-left...

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LeetCode 1893 - Check if All the Integers in a Range Are Covered

LeetCode Problem 1893 Difficulty: 🟢 Easy Topics: Array, Hash Table, Prefix Sum Solution Problem Understanding The problem asks us to determine whether every integer within a given inclusive range [left, right] is covered by at least one of the intervals specified in the ranges array. Each element of ranges is itself an array [starti, endi] representing an inclusive interval, meaning the integers starti and endi are part of the interval....

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LeetCode 3147 - Taking Maximum Energy From the Mystic Dungeon

LeetCode Problem 3147 Difficulty: 🟡 Medium Topics: Array, Dynamic Programming, Prefix Sum Solution Problem Understanding The problem asks us to maximize the total energy gained from a sequence of magicians arranged in a line, where each magician provides a certain energy value, which can be negative or positive. The catch is that after taking energy from a magician at index i , you are instantly teleported to magician (i +...

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LeetCode 2602 - Minimum Operations to Make All Array Elements Equal

LeetCode Problem 2602 Difficulty: 🟡 Medium Topics: Array, Binary Search, Sorting, Prefix Sum Solution Problem Understanding The problem gives us an integer array nums and another array queries . For every query value q , we must calculate the minimum number of operations required to make every element in nums equal to q . One operation consists of increasing or decreasing a single element by exactly 1 . Since each...

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LeetCode 2955 - Number of Same-End Substrings

LeetCode Problem 2955 Difficulty: 🟡 Medium Topics: Array, Hash Table, String, Counting, Prefix Sum Solution Problem Understanding The problem asks us to compute the number of same-end substrings within specified subranges of a given string s . A substring is same-end if its first and last character are identical. We are given multiple queries in the form [li, ri] , each representing a substring s[li..ri] . For each query, we...

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LeetCode 2680 - Maximum OR

LeetCode Problem 2680 Difficulty: 🟡 Medium Topics: Array, Greedy, Bit Manipulation, Prefix Sum Solution Problem Understanding In this problem, we are given an integer array nums and an integer k . We may perform at most k operations, where each operation selects one element and multiplies it by 2 . Multiplying by 2 in binary is equivalent to shifting all bits one position to the left. For example: 5 in...

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LeetCode 2528 - Maximize the Minimum Powered City

LeetCode Problem 2528 Difficulty: 🔴 Hard Topics: Array, Binary Search, Greedy, Queue, Sliding Window, Prefix Sum Solution Problem Understanding The problem asks us to determine the maximum possible minimum power that any city can have after optimally adding k new power stations to an existing configuration. Each city already has some power stations, and each station has a range r over which it contributes to the power of nearby cities....

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LeetCode 1878 - Get Biggest Three Rhombus Sums in a Grid

LeetCode Problem 1878 Difficulty: 🟡 Medium Topics: Array, Math, Sorting, Heap (Priority Queue), Matrix, Prefix Sum Solution Problem Understanding The problem asks us to compute the largest three distinct rhombus sums in a given m x n integer grid. A rhombus in this context is a square rotated 45 degrees, whose corners align with grid cells. The rhombus sum includes only the border cells of this shape, not the interior....

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LeetCode 2389 - Longest Subsequence With Limited Sum

LeetCode Problem 2389 Difficulty: 🟢 Easy Topics: Array, Binary Search, Greedy, Sorting, Prefix Sum Solution Problem Understanding This problem asks us to determine, for each query, the maximum number of elements we can select from an array nums such that their sum does not exceed a given value. We are not required to maintain consecutive elements, only the relative order for subsequences, but in this problem the relative order does...

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LeetCode 3086 - Minimum Moves to Pick K Ones

LeetCode Problem 3086 Difficulty: 🔴 Hard Topics: Array, Greedy, Sliding Window, Prefix Sum Solution Exploration The reviewer identified a sign error in the swap argument, so the first task is to determine the correct monotonicity direction before rebuilding the proof. For $n=1$, there is only one permutation, so the statement is trivial. For $n=2$, take $$x_1=5,\quad x_2=2,\quad y_1=4,\quad y_2=1.$$ The ordered pairing gives $$(5-4)^2+(2-1)^2=1+1=2.$$ The swapped pairing gives $$(5-1)^2+(2-4)^2=16+4=20.$$ Thus...

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LeetCode 1856 - Maximum Subarray Min-Product

LeetCode Problem 1856 Difficulty: 🟡 Medium Topics: Array, Stack, Monotonic Stack, Prefix Sum Solution Problem Understanding The problem asks us to find the maximum min-product of any contiguous subarray of a given integer array nums . The min-product of a subarray is defined as the minimum value in that subarray multiplied by the sum of all elements in that subarray . We are asked to return this maximum value modulo...

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LeetCode 2819 - Minimum Relative Loss After Buying Chocolates

LeetCode Problem 2819 Difficulty: 🔴 Hard Topics: Array, Binary Search, Sorting, Prefix Sum Solution LeetCode 2819 - Minimum Relative Loss After Buying Chocolates Problem Understanding We are given an array prices , where each value represents the price of a chocolate. For every query [k, m] , Bob wants to choose exactly m chocolates. The payment rule depends on the threshold k : If a chocolate costs at most k...

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LeetCode 3356 - Zero Array Transformation II

LeetCode Problem 3356 Difficulty: 🟡 Medium Topics: Array, Two Pointers, Binary Search, Prefix Sum Solution Problem Understanding The problem asks us to determine the minimum number of sequential queries required to transform an array nums into a Zero Array , where all elements are zero. Each query specifies a subarray [li, ri] and a value vali . We are allowed to decrement each element within that subarray by any value...

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LeetCode 2906 - Construct Product Matrix

LeetCode Problem 2906 Difficulty: 🟡 Medium Topics: Array, Matrix, Prefix Sum Solution Problem Understanding The problem asks us to construct a new matrix p from a given matrix grid . For every position (i, j) , the value p[i][j] must equal the product of every element in the matrix except grid[i][j] , and the result must be taken modulo 12345 . In other words, if the matrix contains k =...

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LeetCode 3251 - Find the Count of Monotonic Pairs II

LeetCode Problem 3251 Difficulty: 🔴 Hard Topics: Array, Math, Dynamic Programming, Combinatorics, Prefix Sum Solution Problem Understanding The problem asks us to count the number of ways we can split an array of positive integers, nums , into two arrays, arr1 and arr2 , such that they satisfy a set of monotonic conditions. Specifically, arr1 must be non-decreasing, arr2 must be non-increasing, and for each index i , their sum...

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LeetCode 2207 - Maximize Number of Subsequences in a String

LeetCode Problem 2207 Difficulty: 🟡 Medium Topics: String, Greedy, Prefix Sum Solution Problem Understanding This problem asks us to maximize the number of times a two-character string pattern occurs as a subsequence in a given string text , after inserting exactly one character . The character we can insert is restricted to being either pattern[0] or pattern[1] , and it can be inserted at any position, including the beginning or...

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LeetCode 3096 - Minimum Levels to Gain More Points

LeetCode Problem 3096 Difficulty: 🟡 Medium Topics: Array, Prefix Sum Solution Problem Understanding This problem is asking us to determine the minimum number of levels Alice should play in order to score more points than Bob , given that both play optimally and that some levels may be impossible to clear. The input is a binary array possible of length n . A 1 indicates a level can always be...

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LeetCode 3347 - Maximum Frequency of an Element After Performing Operations II

LeetCode Problem 3347 Difficulty: 🔴 Hard Topics: Array, Binary Search, Sliding Window, Sorting, Prefix Sum Solution LeetCode 3347 - Maximum Frequency of an Element After Performing Operations II Problem Understanding The problem gives us an integer array nums , along with two integers, k and numOperations . We are allowed to perform exactly numOperations operations. In each operation: We must choose an index that has not been used before. We...

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LeetCode 2391 - Minimum Amount of Time to Collect Garbage

LeetCode Problem 2391 Difficulty: 🟡 Medium Topics: Array, String, Prefix Sum Solution Problem Understanding This problem models a garbage collection system with three separate garbage trucks: One truck collects metal garbage, represented by 'M' One truck collects paper garbage, represented by 'P' One truck collects glass garbage, represented by 'G' The input array garbage describes the garbage present at each house. For example, if garbage[i] = "GMP" , then house...

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LeetCode 3225 - Maximum Score From Grid Operations

LeetCode Problem 3225 Difficulty: 🔴 Hard Topics: Array, Dynamic Programming, Matrix, Prefix Sum Solution Problem Understanding This problem presents a 2D square matrix grid of size n x n where each cell contains a non-negative integer. Initially, all cells are white. An operation consists of selecting a cell (i, j) and coloring black all cells in column j from the top (row 0) down to row i . After performing...

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LeetCode 3279 - Maximum Total Area Occupied by Pistons

LeetCode Problem 3279 Difficulty: 🔴 Hard Topics: Array, Hash Table, String, Simulation, Counting, Prefix Sum Solution Problem Understanding This problem is about simulating the motion of pistons in a car engine and computing the maximum total area under the pistons over time. Each piston moves either up or down by 1 unit every second, reversing direction when it hits the top ( height ) or bottom ( 0 ). The...

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LeetCode 1959 - Minimum Total Space Wasted With K Resizing Operations

LeetCode Problem 1959 Difficulty: 🟡 Medium Topics: Array, Dynamic Programming, Prefix Sum Solution Let's go through a full, detailed technical solution guide for LeetCode 1959 following your formatting and style rules. Problem Understanding This problem asks us to minimize the total wasted space when resizing a dynamic array multiple times. We are given a 0-indexed array nums where nums[i] represents the number of elements that need to fit in the...

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LeetCode 1895 - Largest Magic Square

LeetCode Problem 1895 Difficulty: 🟡 Medium Topics: Array, Matrix, Prefix Sum Solution Problem Understanding The problem asks us to find the largest magic square inside a given m x n grid. A magic square is a k x k subgrid where the sum of each row, the sum of each column, and the sums of the two main diagonals are all equal. The input is a 2D array of integers,...

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LeetCode 2483 - Minimum Penalty for a Shop

LeetCode Problem 2483 Difficulty: 🟡 Medium Topics: String, Prefix Sum Solution Problem Understanding The problem asks us to determine the optimal hour to close a shop to minimize a penalty based on customer arrivals. The input is a string customers where each character represents an hour: 'Y' means customers arrive, and 'N' means no customers arrive. The shop can close at any hour from 0 to n (inclusive), and the...

Practice › LeetCode › LeetCode 26xx ›

LeetCode 2615 - Sum of Distances

LeetCode Problem 2615 Difficulty: 🟡 Medium Topics: Array, Hash Table, Prefix Sum Solution Problem Understanding The problem asks us to compute, for every index i in the array nums , the total distance between i and every other index j where nums[j] == nums[i] . More formally, for each position i , we need to calculate: $$\sum |i - j|$$ for all indices j such that: nums[j] == nums[i] j...

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LeetCode 2536 - Increment Submatrices by One

LeetCode Problem 2536 Difficulty: 🟡 Medium Topics: Array, Matrix, Prefix Sum Solution

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LeetCode 1872 - Stone Game VIII

LeetCode Problem 1872 Difficulty: 🔴 Hard Topics: Array, Math, Dynamic Programming, Prefix Sum, Game Theory Solution Problem Understanding The problem describes a two-player turn-based game between Alice and Bob with a row of stones, each having an integer value. The key rules are that on a turn, a player removes more than one stone from the left , sums their values to their score, and then places a new stone...

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LeetCode 2478 - Number of Beautiful Partitions

LeetCode Problem 2478 Difficulty: 🔴 Hard Topics: String, Dynamic Programming, Prefix Sum Solution Problem Understanding The problem asks us to count the number of ways to split a given string s of digits into exactly k non-overlapping substrings, where each substring satisfies specific rules: it must start with a prime digit ( 2 , 3 , 5 , 7 ), end with a non-prime digit ( 1 , 4 ,...

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LeetCode 2100 - Find Good Days to Rob the Bank

LeetCode Problem 2100 Difficulty: 🟡 Medium Topics: Array, Dynamic Programming, Prefix Sum Solution Problem Understanding The problem asks us to find all days that are "good" for robbing a bank based on the number of guards on duty over a period of days. You are given an array security where each element represents the number of guards on a specific day, and an integer time that defines a window before...

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LeetCode 2950 - Number of Divisible Substrings

LeetCode Problem 2950 Difficulty: 🟡 Medium Topics: Hash Table, String, Counting, Prefix Sum Solution Problem Understanding The problem asks us to analyze a given string word where each lowercase English letter is mapped to a digit according to a classic phone keypad scheme. A substring of the string is considered divisible if the sum of the mapped digits of its characters is divisible by the length of the substring. The...

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LeetCode 2448 - Minimum Cost to Make Array Equal

LeetCode Problem 2448 Difficulty: 🔴 Hard Topics: Array, Binary Search, Greedy, Sorting, Prefix Sum Solution This guide will use the weighted median optimization approach, which is the key insight behind solving this problem efficiently within the constraints. Problem Understanding The problem gives us two arrays, nums and cost , each of length n . The nums[i] value represents the current number at index i , and cost[i] represents how expensive...

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LeetCode 2245 - Maximum Trailing Zeros in a Cornered Path

LeetCode Problem 2245 Difficulty: 🟡 Medium Topics: Array, Matrix, Prefix Sum Solution Problem Understanding This problem asks us to find a path in a matrix whose product contains the maximum possible number of trailing zeros. A trailing zero in a number is created by a factor of 10, and every factor of 10 comes from one factor of 2 paired with one factor of 5. Therefore, the number of trailing...

Practice › LeetCode › LeetCode 18xx ›

LeetCode 1871 - Jump Game VII

LeetCode Problem 1871 Difficulty: 🟡 Medium Topics: String, Dynamic Programming, Sliding Window, Prefix Sum Solution Problem Understanding The problem gives us a binary string s , where each character is either '0' or '1' . We start at index 0 , and the problem guarantees that s[0] == '0' , meaning the starting position is always valid. From any index i , we are allowed to jump to another index...

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LeetCode 3361 - Shift Distance Between Two Strings

LeetCode Problem 3361 Difficulty: 🟡 Medium Topics: Array, String, Prefix Sum Solution Problem Understanding The problem gives us two strings, s and t , of equal length. We want to transform s into t character by character using cyclic alphabet shifts. For every character in s , we are allowed to repeatedly perform one of two operations: Shift the character forward to the next letter in the alphabet. Shift the...

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LeetCode 3250 - Find the Count of Monotonic Pairs I

LeetCode Problem 3250 Difficulty: 🔴 Hard Topics: Array, Math, Dynamic Programming, Combinatorics, Prefix Sum Solution Problem Understanding The problem asks us to count the number of valid pairs of arrays (arr1, arr2) derived from a given array nums . Both arr1 and arr2 have the same length as nums . The constraints on these arrays are: arr1 is non-decreasing . arr2 is non-increasing . At each index i , the...

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LeetCode 1943 - Describe the Painting

LeetCode Problem 1943 Difficulty: 🟡 Medium Topics: Array, Hash Table, Sorting, Prefix Sum Solution Problem Understanding The problem describes a painting laid out on a number line. Each segment of the painting is represented as a half-closed interval [start, end) and is painted with a unique color value. Since multiple segments may overlap, different colors can exist simultaneously over the same region. Instead of returning the actual set of colors...

Practice › LeetCode › LeetCode 26xx ›

LeetCode 2640 - Find the Score of All Prefixes of an Array

LeetCode Problem 2640 Difficulty: 🟡 Medium Topics: Array, Prefix Sum Solution Problem Understanding The problem requires calculating a score for all prefixes of an array . Given an integer array nums , we first define a conversion array for any prefix of nums . The conversion array is constructed by adding each element in the prefix to the maximum element seen so far in that prefix . The score of...

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LeetCode 3362 - Zero Array Transformation III

LeetCode Problem 3362 Difficulty: 🟡 Medium Topics: Array, Two Pointers, Greedy, Sorting, Heap (Priority Queue), Prefix Sum Solution Problem Understanding We are given an integer array nums and a list of interval queries. Each query [l, r] allows us to reduce every element inside that range by at most 1 . The important detail is that the decrement is optional and independent for every index in the range. This means...

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LeetCode 2574 - Left and Right Sum Differences

LeetCode Problem 2574 Difficulty: 🟢 Easy Topics: Array, Prefix Sum Solution Problem Understanding The problem asks us to compute the absolute difference between the sum of elements to the left and the sum of elements to the right for each element in a given array nums . In other words, for every index i , we want to know how different the sums on either side of that index are....

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LeetCode 3130 - Find All Possible Stable Binary Arrays II

LeetCode Problem 3130 Difficulty: 🔴 Hard Topics: Dynamic Programming, Prefix Sum Solution LeetCode 3130 - Find All Possible Stable Binary Arrays II Problem Understanding The problem gives us three integers: zero , the exact number of 0 s that must appear in the array one , the exact number of 1 s that must appear in the array limit , the maximum allowed length of any consecutive block of identical...

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LeetCode 2438 - Range Product Queries of Powers

LeetCode Problem 2438 Difficulty: 🟡 Medium Topics: Array, Bit Manipulation, Prefix Sum Solution Problem Understanding The problem defines a special array called powers . This array is built from the binary representation of n . Every positive integer can be uniquely represented as a sum of powers of two. For example: 15 = 1 + 2 + 4 + 8 13 = 1 + 4 + 8 10 = 2...

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LeetCode 2218 - Maximum Value of K Coins From Piles

LeetCode Problem 2218 Difficulty: 🔴 Hard Topics: Array, Dynamic Programming, Prefix Sum Solution Problem Understanding This problem asks us to maximize the total value of coins collected from multiple piles while following a strict removal rule. Each pile is ordered from top to bottom, meaning we cannot arbitrarily pick any coin in a pile. We may only remove coins from the top, one at a time. If we want a...

Practice › LeetCode › LeetCode 25xx ›

LeetCode 2505 - Bitwise OR of All Subsequence Sums

LeetCode Problem 2505 Difficulty: 🟡 Medium Topics: Array, Math, Bit Manipulation, Brainteaser, Prefix Sum Solution LeetCode 2505 - Bitwise OR of All Subsequence Sums Problem Understanding This problem asks us to compute the bitwise OR of every possible subsequence sum of a given array. A subsequence is formed by choosing any subset of elements while preserving their original order. Since every element can either be included or excluded, an array...

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LeetCode 2875 - Minimum Size Subarray in Infinite Array

LeetCode Problem 2875 Difficulty: 🟡 Medium Topics: Array, Hash Table, Sliding Window, Prefix Sum Solution LeetCode 2875 - Minimum Size Subarray in Infinite Array Problem Understanding This problem gives us a finite array nums , but asks us to imagine an infinite array called infinite_nums created by repeating nums forever. For example: nums = [1, 2, 3] infinite_nums = [1,2,3,1,2,3,1,2,3,1,2,3,...] We must find the shortest contiguous subarray in this infinite...

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LeetCode 2055 - Plates Between Candles

LeetCode Problem 2055 Difficulty: 🟡 Medium Topics: Array, String, Binary Search, Prefix Sum Solution Problem Understanding The problem gives us a string s made of two characters: '*' represents a plate '|' represents a candle We are also given multiple queries, where each query specifies a substring of s using indices [left, right] . For every query, we must count how many plates are located between two candles inside that...

Practice › LeetCode › LeetCode 33xx ›

LeetCode 3364 - Minimum Positive Sum Subarray

LeetCode Problem 3364 Difficulty: 🟢 Easy Topics: Array, Sliding Window, Prefix Sum Solution Problem Understanding The problem asks us to find the smallest positive sum among all subarrays whose lengths fall within a given range [l, r] . A subarray is a contiguous section of the array. We are allowed to choose any non-empty contiguous segment as long as: Its length is between l and r , inclusive. Its sum...

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LeetCode 2234 - Maximum Total Beauty of the Gardens

LeetCode Problem 2234 Difficulty: 🔴 Hard Topics: Array, Two Pointers, Binary Search, Greedy, Sorting, Enumeration, Prefix Sum Solution Problem Understanding In this problem, we are given several gardens, where flowers[i] represents how many flowers are already planted in the i-th garden. We are also given a limited number of additional flowers, newFlowers , that we may distribute among the gardens. The goal is to maximize the total beauty score after...

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LeetCode 3129 - Find All Possible Stable Binary Arrays I

LeetCode Problem 3129 Difficulty: 🟡 Medium Topics: Dynamic Programming, Prefix Sum Solution Problem Understanding In this problem, we need to count how many binary arrays can be formed using exactly zero copies of 0 and exactly one copies of 1 , while satisfying an additional stability condition. A binary array is considered stable if every subarray whose length is greater than limit contains both 0 and 1 . Another way...

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LeetCode 1991 - Find the Middle Index in Array

LeetCode Problem 1991 Difficulty: 🟢 Easy Topics: Array, Prefix Sum Solution LeetCode 1991 - Find the Middle Index in Array Problem Understanding The problem gives us a 0-indexed integer array called nums . We need to find an index such that the sum of all elements to the left of that index is equal to the sum of all elements to the right of that index. More formally, for an...

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LeetCode 2256 - Minimum Average Difference

LeetCode Problem 2256 Difficulty: 🟡 Medium Topics: Array, Prefix Sum Solution Problem Understanding In this problem, we are given a 0-indexed integer array nums , and for every index i , we must compute something called the "average difference". For a particular index i , the array is split into two parts: The left part contains elements from index 0 through i The right part contains elements from index i...

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LeetCode 2485 - Find the Pivot Integer

LeetCode Problem 2485 Difficulty: 🟢 Easy Topics: Math, Prefix Sum Solution LeetCode 2485 - Find the Pivot Integer Problem Understanding The problem gives us a positive integer n and asks us to find a special integer x , called the pivot integer, such that: The sum of all integers from 1 to x is equal to The sum of all integers from x to n The important detail is that...

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LeetCode 2772 - Apply Operations to Make All Array Elements Equal to Zero

LeetCode Problem 2772 Difficulty: 🟡 Medium Topics: Array, Prefix Sum Solution Problem Understanding The problem gives us an integer array nums and an integer k . We are allowed to repeatedly choose any contiguous subarray of length k and decrease every element inside that subarray by 1 . Our goal is to determine whether it is possible to make every element in the array equal to 0 after performing any...

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LeetCode 2588 - Count the Number of Beautiful Subarrays

LeetCode Problem 2588 Difficulty: 🟡 Medium Topics: Array, Hash Table, Bit Manipulation, Prefix Sum Solution Problem Understanding The problem gives us an array nums , and we are allowed to repeatedly perform a special operation on pairs of elements. In one operation, we choose two different indices i and j , and also choose a bit position k such that both nums[i] and nums[j] currently have the k th bit...

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LeetCode 2587 - Rearrange Array to Maximize Prefix Score

LeetCode Problem 2587 Difficulty: 🟡 Medium Topics: Array, Greedy, Sorting, Prefix Sum Solution Problem Understanding The problem gives us a 0-indexed array of integers , nums , which can include negative numbers, zero, and positive numbers. We are allowed to reorder the elements in any way we choose. After reordering, we compute the prefix sum array , prefix , where prefix[i] is the sum of all elements from index 0...

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LeetCode 3355 - Zero Array Transformation I

LeetCode Problem 3355 Difficulty: 🟡 Medium Topics: Array, Prefix Sum Solution Problem Understanding The problem asks whether it is possible to transform a given integer array nums into a Zero Array , where all elements are zero, using a series of decrement operations defined by queries . Each query specifies a range [li, ri] in which we can select any subset of indices to decrement by 1. The operation can...

Practice › LeetCode › LeetCode 29xx ›

LeetCode 2947 - Count Beautiful Substrings I

LeetCode Problem 2947 Difficulty: 🟡 Medium Topics: Hash Table, Math, String, Enumeration, Number Theory, Prefix Sum Solution LeetCode 2947 - Count Beautiful Substrings I Problem Understanding We are given a lowercase English string s and a positive integer k . We must count how many non-empty substrings satisfy the definition of a beautiful substring. For a substring, let: vowels be the number of vowel characters ( a , e ,...

Practice › LeetCode › LeetCode 22xx ›

LeetCode 2222 - Number of Ways to Select Buildings

LeetCode Problem 2222 Difficulty: 🟡 Medium Topics: String, Dynamic Programming, Prefix Sum Solution Problem Understanding The problem asks us to count the number of ways to select exactly 3 buildings from a street represented as a binary string s , such that no two consecutive buildings among the selected ones have the same type. Here, 0 represents an office, and 1 represents a restaurant. Essentially, for the three selected buildings...

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LeetCode 1889 - Minimum Space Wasted From Packaging

LeetCode Problem 1889 Difficulty: 🔴 Hard Topics: Array, Binary Search, Sorting, Prefix Sum Solution Problem Understanding The problem gives us a list of package sizes and several suppliers. Each supplier offers an unlimited number of boxes, but only in certain fixed sizes. We must choose exactly one supplier and pack every package using only the box sizes that supplier provides. Each package must go into a single box whose size...

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LeetCode 3026 - Maximum Good Subarray Sum

LeetCode Problem 3026 Difficulty: 🟡 Medium Topics: Array, Hash Table, Prefix Sum Solution Problem Understanding The problem asks us to find the maximum possible sum of a contiguous subarray where the absolute difference between the first and last element of that subarray is exactly k . More formally, for a subarray nums[i..j] , it is considered good if: $|nums[i]-nums[j]|=k$ We must examine all valid subarrays and return the largest subarray...

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LeetCode 3152 - Special Array II

LeetCode Problem 3152 Difficulty: 🟡 Medium Topics: Array, Binary Search, Prefix Sum Solution Problem Understanding We are given an integer array nums and several queries. Each query specifies a subarray using two indices [fromi, toi] . For every query, we must determine whether the subarray nums[fromi..toi] is a special array. A subarray is considered special if every adjacent pair of elements has different parity. In other words: An even number...

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LeetCode 2219 - Maximum Sum Score of Array

LeetCode Problem 2219 Difficulty: 🟡 Medium Topics: Array, Prefix Sum Solution Problem Understanding The problem gives us a 0-indexed integer array nums of length n and asks us to compute the maximum sum score among all indices of the array. The sum score at index i is defined as the maximum of two sums: the sum of the first i + 1 elements of the array (the prefix sum up...

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LeetCode 2838 - Maximum Coins Heroes Can Collect

LeetCode Problem 2838 Difficulty: 🟡 Medium Topics: Array, Two Pointers, Binary Search, Sorting, Prefix Sum Solution LeetCode 2838 - Maximum Coins Heroes Can Collect Problem Understanding This problem gives us three arrays: heroes , where heroes[i] represents the power of the i th hero. monsters , where monsters[j] represents the power of the j th monster. coins , where coins[j] represents the reward obtained for defeating the j th monster....

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LeetCode 2488 - Count Subarrays With Median K

LeetCode Problem 2488 Difficulty: 🔴 Hard Topics: Array, Hash Table, Prefix Sum Solution Problem Understanding This problem asks us to count how many contiguous subarrays have a median equal to a given value k . The array nums contains every integer from 1 to n exactly once, which means all elements are distinct. That detail is extremely important because it removes ambiguity when comparing values relative to k . The...

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LeetCode 2381 - Shifting Letters II

LeetCode Problem 2381 Difficulty: 🟡 Medium Topics: Array, String, Prefix Sum Solution LeetCode 2381 - Shifting Letters II Problem Understanding This problem gives us a lowercase English string s and a list of shift operations. Each operation is represented as: [start, end, direction] The operation affects every character from index start to index end , inclusive. If direction == 1 , every character in that range is shifted forward by...

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LeetCode 3346 - Maximum Frequency of an Element After Performing Operations I

LeetCode Problem 3346 Difficulty: 🟡 Medium Topics: Array, Binary Search, Sliding Window, Sorting, Prefix Sum Solution Problem Understanding The problem gives us an integer array nums , along with two integers, k and numOperations . We are allowed to perform exactly numOperations operations. In each operation, we must choose a unique index that has not been used before, and modify that element by adding any integer value in the range...

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LeetCode 1930 - Unique Length-3 Palindromic Subsequences

LeetCode Problem 1930 Difficulty: 🟡 Medium Topics: Hash Table, String, Bit Manipulation, Prefix Sum Solution Problem Understanding The problem asks us to count unique palindromic subsequences of length 3 in a given string s . A palindromic string reads the same forwards and backwards, and in this case, we only care about strings of exactly three characters. A subsequence is formed by deleting zero or more characters from the original...

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LeetCode 2209 - Minimum White Tiles After Covering With Carpets

LeetCode Problem 2209 Difficulty: 🔴 Hard Topics: String, Dynamic Programming, Prefix Sum Solution Problem Understanding The problem presents a binary string floor representing a row of tiles, where '0' corresponds to a black tile and '1' corresponds to a white tile. The goal is to cover some of these tiles using a limited number of black carpets of a fixed length, such that the number of white tiles still visible...

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LeetCode 1862 - Sum of Floored Pairs

LeetCode Problem 1862 Difficulty: 🔴 Hard Topics: Array, Math, Binary Search, Counting, Enumeration, Prefix Sum Solution Problem Understanding The problem asks us to calculate the sum of the integer division results, floor(nums[i] / nums[j]) , for every pair of elements (i, j) in a given array nums . Here, floor() represents the largest integer less than or equal to the division result. The array nums can have up to 10^5...

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LeetCode 2145 - Count the Hidden Sequences

LeetCode Problem 2145 Difficulty: 🟡 Medium Topics: Array, Prefix Sum Solution Problem Understanding The problem asks us to determine how many possible sequences of integers exist that match a given array of differences between consecutive elements, while staying within a specified inclusive range. Specifically, you are given an array differences of length n where each element represents the difference between consecutive elements of a hidden sequence of length n +...

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LeetCode 2302 - Count Subarrays With Score Less Than K

LeetCode Problem 2302 Difficulty: 🔴 Hard Topics: Array, Binary Search, Sliding Window, Prefix Sum Solution Problem Understanding The problem asks us to count the number of contiguous subarrays of a given array nums whose score is strictly less than a given threshold k . The score of a subarray is defined as the product of its sum and its length. Formally, for a subarray nums[i:j] with length len = j...

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LeetCode 2439 - Minimize Maximum of Array

LeetCode Problem 2439 Difficulty: 🟡 Medium Topics: Array, Binary Search, Dynamic Programming, Greedy, Prefix Sum Solution Problem Understanding The problem gives a 0-indexed array nums of non-negative integers and allows a specific operation: choose an index i (where 1 <= i < n ) such that nums[i] > 0 , then decrease nums[i] by 1 and increase nums[i - 1] by 1. The task is to perform this operation any...

Practice › LeetCode › LeetCode 32xx ›

LeetCode 3261 - Count Substrings That Satisfy K-Constraint II

LeetCode Problem 3261 Difficulty: 🔴 Hard Topics: Array, String, Binary Search, Sliding Window, Prefix Sum Solution LeetCode 3261 - Count Substrings That Satisfy K-Constraint II Problem Understanding We are given a binary string s , an integer k , and many range queries. For each query [l, r] , we only consider the substring s[l..r] . Among all substrings completely contained inside this range, we must count how many satisfy...

Practice › LeetCode › LeetCode 30xx ›

LeetCode 3070 - Count Submatrices with Top-Left Element and Sum Less Than k

LeetCode Problem 3070 Difficulty: 🟡 Medium Topics: Array, Matrix, Prefix Sum Solution Problem Understanding The problem gives us a 2D integer matrix called grid and an integer k . We need to count how many submatrices satisfy two conditions: The submatrix must contain the top-left cell of the original matrix, which is grid[0][0] . The sum of all elements inside the submatrix must be less than or equal to k...

Practice › LeetCode › LeetCode 23xx ›

LeetCode 2398 - Maximum Number of Robots Within Budget

LeetCode Problem 2398 Difficulty: 🔴 Hard Topics: Array, Binary Search, Queue, Sliding Window, Heap (Priority Queue), Prefix Sum, Monotonic Queue Solution Problem Understanding This problem asks us to determine the maximum number of consecutive robots that can be run without exceeding a given budget. We are given two arrays of length n : chargeTimes and runningCosts . For any consecutive subset of k robots, the total cost is computed as:...

Practice › LeetCode › LeetCode 29xx ›

LeetCode 2983 - Palindrome Rearrangement Queries

LeetCode Problem 2983 Difficulty: 🔴 Hard Topics: Hash Table, String, Prefix Sum Solution Problem Understanding We are given a string s of even length n . For every query, we are allowed to independently rearrange two specific substrings: One substring lies completely inside the left half of the string. The other substring lies completely inside the right half of the string. The goal is to determine whether, after rearranging only...

Practice › LeetCode › LeetCode 22xx ›

LeetCode 2271 - Maximum White Tiles Covered by a Carpet

LeetCode Problem 2271 Difficulty: 🟡 Medium Topics: Array, Binary Search, Greedy, Sliding Window, Sorting, Prefix Sum Solution That is a long-form reference guide request. To avoid truncation and keep the formatting exact, I will provide the complete solution guide for LeetCode 2271 in a single structured response. Problem Understanding The problem gives us a collection of disjoint white tile intervals and a carpet of fixed length. Each interval [li, ri]...

Practice › LeetCode › LeetCode 23xx ›

LeetCode 2382 - Maximum Segment Sum After Removals

LeetCode Problem 2382 Difficulty: 🔴 Hard Topics: Array, Union-Find, Prefix Sum, Ordered Set Solution Problem Understanding The problem gives us two arrays, nums and removeQueries , both of length n . The nums array contains positive integers. Initially, all elements are present, forming one contiguous segment. Then, elements are removed one by one according to the order defined in removeQueries . After each removal, the array becomes split into one...

Practice › LeetCode › LeetCode 30xx ›

LeetCode 3077 - Maximum Strength of K Disjoint Subarrays

LeetCode Problem 3077 Difficulty: 🔴 Hard Topics: Array, Dynamic Programming, Prefix Sum Solution Problem Understanding The problem is asking us to select exactly k disjoint subarrays from a given array nums such that the last element of each subarray comes before the first element of the next subarray. The goal is to maximize a weighted sum called strength , where the weight decreases by 1 for each subsequent subarray and...

Practice › LeetCode › LeetCode 24xx ›

LeetCode 2406 - Divide Intervals Into Minimum Number of Groups

LeetCode Problem 2406 Difficulty: 🟡 Medium Topics: Array, Two Pointers, Greedy, Sorting, Heap (Priority Queue), Prefix Sum Solution Problem Understanding The problem gives us a list of inclusive intervals, where each interval is represented as [left, right] . We must divide all intervals into groups such that no two intervals inside the same group intersect. The important detail is that the intervals are inclusive. This means two intervals overlap even...

Practice › LeetCode › LeetCode 32xx ›

LeetCode 3212 - Count Submatrices With Equal Frequency of X and Y

LeetCode Problem 3212 Difficulty: 🟡 Medium Topics: Array, Matrix, Prefix Sum Solution Problem Understanding The problem asks us to count submatrices within a given 2D character matrix grid that satisfy three conditions. A submatrix is defined by a contiguous rectangle within the grid, and the submatrix must include the top-left cell grid[0][0] . The first condition is that the submatrix contains equal numbers of 'X' and 'Y' . The second...

Practice › LeetCode › LeetCode 21xx ›

LeetCode 2106 - Maximum Fruits Harvested After at Most K Steps

LeetCode Problem 2106 Difficulty: 🔴 Hard Topics: Array, Binary Search, Sliding Window, Prefix Sum Solution Problem Understanding In this problem, we are given several fruit piles placed on an infinite one dimensional number line. Each pile is represented by a position and the number of fruits available at that position. The input array fruits is already sorted by position, and every position is unique. You start at position startPos ,...

Practice › LeetCode › LeetCode 29xx ›

LeetCode 2971 - Find Polygon With the Largest Perimeter

LeetCode Problem 2971 Difficulty: 🟡 Medium Topics: Array, Greedy, Sorting, Prefix Sum Solution LeetCode 2971 - Find Polygon With the Largest Perimeter Problem Understanding The problem gives us an array nums containing positive integers. Each integer represents a potential side length that we may use when constructing a polygon. A polygon must have at least three sides. The key geometric property we are given is that if the side lengths...

Practice › LeetCode › LeetCode 33xx ›

LeetCode 3312 - Sorted GCD Pair Queries

LeetCode Problem 3312 Difficulty: 🔴 Hard Topics: Array, Hash Table, Math, Binary Search, Combinatorics, Counting, Number Theory, Prefix Sum Solution === 1996-G1 === IMO 1996 Shortlist G1 Origin: GBR Problem Let triangle $ABC$ have orthocenter $H$, and let $P$ be a point on its circumcircle, distinct from $A$, $B$, $C$. Let $E$ be the foot of the altitude $BH$, let $PAQB$ and $PARC$ be parallelograms, and let $AQ$ meet $HR$...

Practice › LeetCode › LeetCode 28xx ›

LeetCode 2845 - Count of Interesting Subarrays

LeetCode Problem 2845 Difficulty: 🟡 Medium Topics: Array, Hash Table, Prefix Sum Solution Problem Understanding The problem is asking us to count the number of interesting subarrays in a given array nums . An interesting subarray is defined by a modular counting condition: within any subarray nums[l..r] , count the number of elements nums[i] where nums[i] % modulo == k . If this count, cnt , also satisfies cnt %...

Practice › LeetCode › LeetCode 21xx ›

LeetCode 2121 - Intervals Between Identical Elements

LeetCode Problem 2121 Difficulty: 🟡 Medium Topics: Array, Hash Table, Prefix Sum Solution LeetCode 2121 - Intervals Between Identical Elements Problem Statement You are given a 0-indexed integer array arr . For every index i , you must compute the sum of distances between i and every other index j where arr[i] == arr[j] . The distance between two indices is the absolute difference of their positions: $$|i - j|$$...

Practice › LeetCode › LeetCode 22xx ›

LeetCode 2270 - Number of Ways to Split Array

LeetCode Problem 2270 Difficulty: 🟡 Medium Topics: Array, Prefix Sum Solution Problem Understanding The problem asks us to determine the number of ways to split a given 0-indexed array nums into two non-empty contiguous subarrays such that the sum of the first part is greater than or equal to the sum of the second part. Formally, a split at index i is valid if sum(nums[0:i+1]) >= sum(nums[i+1:n]) and 0 <=...

Practice › LeetCode › LeetCode 25xx ›

LeetCode 2552 - Count Increasing Quadruplets

LeetCode Problem 2552 Difficulty: 🔴 Hard Topics: Array, Dynamic Programming, Binary Indexed Tree, Enumeration, Prefix Sum Solution Problem Understanding The problem asks us to count the number of increasing quadruplets (i, j, k, l) in a 0-indexed array nums of size n , where nums is a permutation of the integers from 1 to n . A quadruplet is considered increasing if it satisfies both the index order 0 <=...

Practice › LeetCode › LeetCode 24xx ›

LeetCode 2420 - Find All Good Indices

LeetCode Problem 2420 Difficulty: 🟡 Medium Topics: Array, Dynamic Programming, Prefix Sum Solution Problem Understanding The problem asks us to identify all good indices in an array nums based on a window size k . A good index i satisfies two conditions: the k elements immediately before it form a non-increasing sequence, and the k elements immediately after it form a non-decreasing sequence. The input is a 0-indexed array of...

Practice › LeetCode › LeetCode 26xx ›

LeetCode 2681 - Power of Heroes

LeetCode Problem 2681 Difficulty: 🔴 Hard Topics: Array, Math, Dynamic Programming, Sorting, Prefix Sum Solution Problem Understanding The problem asks us to compute the total "power" across every possible non-empty subset of heroes. For any selected group of heroes, its power is defined as: $$(\text{maximum strength in the group})^2 \times (\text{minimum strength in the group})$$ We are given an array nums , where each value represents the strength of one...

Practice › LeetCode › LeetCode 21xx ›

LeetCode 2132 - Stamping the Grid

LeetCode Problem 2132 Difficulty: 🔴 Hard Topics: Array, Greedy, Matrix, Prefix Sum Solution Problem Understanding In this problem, we are given a binary matrix called grid . Every cell contains either: 0 , meaning the cell is empty 1 , meaning the cell is blocked or occupied We are also given a rectangular stamp with dimensions: stampHeight stampWidth The goal is to determine whether it is possible to place any...

Practice › LeetCode › LeetCode 19xx ›

LeetCode 1915 - Number of Wonderful Substrings

LeetCode Problem 1915 Difficulty: 🟡 Medium Topics: Hash Table, String, Bit Manipulation, Prefix Sum Solution LeetCode 1915, Number of Wonderful Substrings Problem Understanding The problem asks us to count how many non-empty substrings of a given string are considered "wonderful". A substring is wonderful if at most one character appears an odd number of times inside that substring. The string only contains characters from 'a' to 'j' , which means...

Practice › LeetCode › LeetCode 21xx ›

LeetCode 2171 - Removing Minimum Number of Magic Beans

LeetCode Problem 2171 Difficulty: 🟡 Medium Topics: Array, Greedy, Sorting, Enumeration, Prefix Sum Solution Problem Understanding The problem asks us to remove beans from bags in such a way that all non-empty bags have the same number of beans while minimizing the total number of beans removed. Each element in the input array beans represents a bag with a positive number of beans. We are allowed to remove any number...

Practice › LeetCode › LeetCode 30xx ›

LeetCode 3015 - Count the Number of Houses at a Certain Distance I

LeetCode Problem 3015 Difficulty: 🟡 Medium Topics: Breadth-First Search, Graph Theory, Prefix Sum Solution Here is a complete technical solution guide for LeetCode 3015 - Count the Number of Houses at a Certain Distance I , formatted according to your specifications. Problem Understanding The problem describes a simple linear city with n houses numbered from 1 to n . Each consecutive house i and i + 1 are connected by...

Practice › LeetCode › LeetCode 24xx ›

LeetCode 2489 - Number of Substrings With Fixed Ratio

LeetCode Problem 2489 Difficulty: 🟡 Medium Topics: Hash Table, Math, String, Prefix Sum Solution Problem Understanding The problem gives us a binary string s , along with two coprime integers num1 and num2 . We need to count how many non-empty substrings contain 0 s and 1 s in the exact ratio num1 : num2 . If a substring contains: zeroCount zeros oneCount ones then it is valid only if:...

Practice › LeetCode › LeetCode 25xx ›

LeetCode 2559 - Count Vowel Strings in Ranges

LeetCode Problem 2559 Difficulty: 🟡 Medium Topics: Array, String, Prefix Sum Solution Problem Understanding The problem gives us an array of strings called words and a list of range queries called queries . For each query [li, ri] , we must determine how many strings in words between indices li and ri , inclusive, both start and end with a vowel. The vowels are limited to the lowercase English vowels:...

Practice › LeetCode › LeetCode 22xx ›

LeetCode 2251 - Number of Flowers in Full Bloom

LeetCode Problem 2251 Difficulty: 🔴 Hard Topics: Array, Hash Table, Binary Search, Sorting, Prefix Sum, Ordered Set Solution Problem Understanding The problem asks us to determine, for a list of people arriving at certain times, how many flowers are in full bloom at the time of their arrival. Each flower has a start and end time representing the period it is in full bloom, inclusive of both endpoints. The input...

Practice › LeetCode › LeetCode 31xx ›

LeetCode 3179 - Find the N-th Value After K Seconds

LeetCode Problem 3179 Difficulty: 🟡 Medium Topics: Array, Math, Simulation, Combinatorics, Prefix Sum Solution Problem Understanding The problem requires computing the value of the last element in an array after a series of sequential cumulative sum operations over a fixed number of seconds. You start with an array a of length n where all elements are initialized to 1. Every second, each element at index i becomes the sum of...

Practice › LeetCode › LeetCode 18xx ›

LeetCode 1854 - Maximum Population Year

LeetCode Problem 1854 Difficulty: 🟢 Easy Topics: Array, Counting, Prefix Sum Solution Problem Understanding The problem asks us to determine the year with the highest population given a list of birth and death years. Each element in the input logs is a pair [birthi, deathi] representing the inclusive start of life at birthi and exclusive end at deathi . In other words, a person is considered alive from their birth...

Practice › LeetCode › LeetCode 18xx ›

LeetCode 1894 - Find the Student that Will Replace the Chalk

LeetCode Problem 1894 Difficulty: 🟡 Medium Topics: Array, Binary Search, Simulation, Prefix Sum Solution Problem Understanding The problem presents a classroom scenario where students are given problems in a round-robin order, consuming a certain number of chalk pieces for each problem. We are given an array chalk , where chalk[i] indicates the number of chalk pieces student i uses, and an integer k representing the initial chalk supply. Starting from...

Practice › LeetCode › LeetCode 30xx ›

LeetCode 3017 - Count the Number of Houses at a Certain Distance II

LeetCode Problem 3017 Difficulty: 🔴 Hard Topics: Graph Theory, Prefix Sum Solution Problem Understanding We are given a graph of n houses arranged in a straight line. Normally, every house i is connected to i + 1 , so the graph forms a simple path: 1 - 2 - 3 - ... - n In addition to these standard edges, there is one extra street connecting house x and house...

Practice › LeetCode › LeetCode 22xx ›

LeetCode 2281 - Sum of Total Strength of Wizards

LeetCode Problem 2281 Difficulty: 🔴 Hard Topics: Array, Stack, Monotonic Stack, Prefix Sum Solution Problem Understanding The problem asks us to compute the sum of total strengths across every possible contiguous subarray of the input array strength . For any chosen subarray, its total strength is defined as: $$\text{minimum value in subarray} \times \text{sum of values in subarray}$$ We must evaluate this quantity for all non-empty contiguous subarrays , then...

Practice › LeetCode › LeetCode 19xx ›

LeetCode 1983 - Widest Pair of Indices With Equal Range Sum

LeetCode Problem 1983 Difficulty: 🟡 Medium Topics: Array, Hash Table, Prefix Sum Solution Problem Understanding The problem asks us to find the widest subarray (continuous segment) in two binary arrays nums1 and nums2 such that the sum of elements in that segment is equal for both arrays. Formally, we need to find indices (i, j) with i <= j such that: sum(nums1[i..j]) == sum(nums2[i..j]) and maximize the distance j -...

Practice › LeetCode › LeetCode 29xx ›

LeetCode 2949 - Count Beautiful Substrings II

LeetCode Problem 2949 Difficulty: 🔴 Hard Topics: Hash Table, Math, String, Number Theory, Prefix Sum Solution Problem Understanding The problem asks us to find the number of non-empty substrings in a given string s that satisfy two conditions simultaneously. First, the substring must have an equal number of vowels and consonants. Second, the product of the number of vowels and consonants must be divisible by a given integer k ....

Practice › LeetCode › LeetCode 05xx ›

LeetCode 523 - Continuous Subarray Sum

LeetCode Problem 523 Difficulty: 🟡 Medium Topics: Array, Hash Table, Math, Prefix Sum Solution Problem Understanding The problem asks us to determine whether an array contains a continuous subarray whose sum is a multiple of k , while also satisfying an important constraint: the subarray must contain at least two elements . In simpler terms, we need to find whether there exists some contiguous segment of nums , with length...

Practice › LeetCode › LeetCode 14xx ›

LeetCode 1480 - Running Sum of 1d Array

LeetCode Problem 1480 Difficulty: 🟢 Easy Topics: Array, Prefix Sum Solution LeetCode 1480 - Running Sum of 1d Array Problem Understanding The problem asks us to compute the running sum, also called the prefix sum, of a one dimensional integer array. For every index i , the result at position i should equal the sum of all elements from index 0 through index i in the original array. In other...

Practice › LeetCode › LeetCode 16xx ›

LeetCode 1685 - Sum of Absolute Differences in a Sorted Array

LeetCode Problem 1685 Difficulty: 🟡 Medium Topics: Array, Math, Prefix Sum Solution Problem Understanding The problem gives us a sorted integer array nums , arranged in non-decreasing order. For every index i , we must compute the total sum of absolute differences between nums[i] and every other element in the array. Formally, for each position i : $$result[i] = \sum_{j=0}^{n-1} |nums[i] - nums[j]|$$ The output must be an array of...

Practice › LeetCode › LeetCode 10xx ›

LeetCode 1004 - Max Consecutive Ones III

LeetCode Problem 1004 Difficulty: 🟡 Medium Topics: Array, Binary Search, Sliding Window, Prefix Sum Solution Problem Understanding This problem asks us to find the length of the longest contiguous subarray that can contain only 1 s after flipping at most k zeroes into ones. The input consists of: A binary array nums , where every element is either 0 or 1 An integer k , representing the maximum number of...

Practice › LeetCode › LeetCode 07xx ›

LeetCode 731 - My Calendar II

LeetCode Problem 731 Difficulty: 🟡 Medium Topics: Array, Binary Search, Design, Segment Tree, Prefix Sum, Ordered Set Solution Problem Understanding The problem asks us to design a calendar system that supports booking time intervals while enforcing one important rule: no point in time may be covered by three events simultaneously. Each event is represented as a half open interval [startTime, endTime) . This means the event includes startTime but excludes...

Practice › LeetCode › LeetCode 16xx ›

LeetCode 1621 - Number of Sets of K Non-Overlapping Line Segments

LeetCode Problem 1621 Difficulty: 🟡 Medium Topics: Math, Dynamic Programming, Combinatorics, Prefix Sum Solution This guide is quite large and highly detailed under your required structure, especially with full worked examples, both Python and Go implementations, brute force plus optimal approaches, proof sketch, extensive test cases, and edge case analysis. To keep quality high and avoid truncation, I will provide it in a structured, comprehensive format. I will use the...

Practice › LeetCode › LeetCode 11xx ›

LeetCode 1109 - Corporate Flight Bookings

LeetCode Problem 1109 Difficulty: 🟡 Medium Topics: Array, Prefix Sum Solution Problem Understanding The problem is asking us to compute the total number of seats reserved for each flight given a list of flight bookings. Each booking specifies a range of consecutive flights [firsti, lasti] and the number of seats seatsi reserved for each flight in that range. The flights are numbered from 1 to n , and the result...

Practice › LeetCode › LeetCode 16xx ›

LeetCode 1687 - Delivering Boxes from Storage to Ports

LeetCode Problem 1687 Difficulty: 🔴 Hard Topics: Array, Dynamic Programming, Segment Tree, Queue, Heap (Priority Queue), Prefix Sum, Monotonic Queue Solution Problem Understanding This problem asks us to minimize the total number of ship trips required to deliver boxes from storage to ports, while respecting two constraints: The ship can carry at most maxBoxes boxes at once. The total weight of the loaded boxes cannot exceed maxWeight . The boxes...

Practice › LeetCode › LeetCode 06xx ›

LeetCode 689 - Maximum Sum of 3 Non-Overlapping Subarrays

LeetCode Problem 689 Difficulty: 🔴 Hard Topics: Array, Dynamic Programming, Sliding Window, Prefix Sum Solution Problem Understanding The problem asks us to select exactly three non-overlapping subarrays from the input array nums , where each subarray has length k . Among all valid choices, we must maximize the total sum of all elements contained in those three subarrays. The output is not the subarrays themselves, but the starting indices of...

Practice › LeetCode › LeetCode 14xx ›

LeetCode 1444 - Number of Ways of Cutting a Pizza

LeetCode Problem 1444 Difficulty: 🔴 Hard Topics: Array, Dynamic Programming, Memoization, Matrix, Prefix Sum Solution Edit LeetCode 1444 - Number of Ways of Cutting a Pizza Problem Understanding This problem asks us to count the number of valid ways to divide a rectangular pizza into exactly k pieces such that every piece contains at least one apple. The pizza is represented as a grid of characters where 'A' indicates an...

Practice › LeetCode › LeetCode 02xx ›

LeetCode 253 - Meeting Rooms II

LeetCode Problem 253 Difficulty: 🟡 Medium Topics: Array, Two Pointers, Greedy, Sorting, Heap (Priority Queue), Prefix Sum Solution Problem Understanding The problem gives us a list of meeting intervals where each interval is represented as [start, end] . Each interval describes the time range during which a meeting occupies a conference room. The goal is to determine the minimum number of conference rooms needed so that all meetings can take...

Practice › LeetCode › LeetCode 11xx ›

LeetCode 1140 - Stone Game II

LeetCode Problem 1140 Difficulty: 🟡 Medium Topics: Array, Math, Dynamic Programming, Prefix Sum, Game Theory Solution Problem Understanding The problem is a two-player turn-based game played on a row of stone piles. Each pile has a positive number of stones, and players take turns taking stones from the start of the remaining piles. On each turn, a player can take up to 2 * M piles, where M starts at...

Practice › LeetCode › LeetCode 03xx ›

LeetCode 325 - Maximum Size Subarray Sum Equals k

LeetCode Problem 325 Difficulty: 🟡 Medium Topics: Array, Hash Table, Prefix Sum Solution Problem Understanding The problem asks us to find the longest contiguous subarray whose sum is exactly equal to a given integer k . A subarray is a continuous portion of the array. This means we cannot reorder elements or skip positions. We must choose a start index and an end index such that every element between them...

Practice › LeetCode › LeetCode 05xx ›

LeetCode 528 - Random Pick with Weight

LeetCode Problem 528 Difficulty: 🟡 Medium Topics: Array, Math, Binary Search, Prefix Sum, Randomized Solution Problem Understanding The problem asks us to design a data structure that supports weighted random sampling . You are given an array w , where each element represents the weight of an index. Instead of choosing every index with equal probability, the selection probability depends on its weight. For example: If w = [1, 3]...

Practice › LeetCode › LeetCode 15xx ›

LeetCode 1546 - Maximum Number of Non-Overlapping Subarrays With Sum Equals Target

LeetCode Problem 1546 Difficulty: 🟡 Medium Topics: Array, Hash Table, Greedy, Prefix Sum Solution Problem Understanding This problem asks us to find the maximum number of non-overlapping subarrays in a given integer array nums such that the sum of each subarray equals a given target . In simpler terms, we are scanning the array to find consecutive sequences of numbers whose sum matches target and ensuring that no two chosen...

Practice › LeetCode › LeetCode 17xx ›

LeetCode 1738 - Find Kth Largest XOR Coordinate Value

LeetCode Problem 1738 Difficulty: 🟡 Medium Topics: Array, Divide and Conquer, Bit Manipulation, Sorting, Heap (Priority Queue), Matrix, Prefix Sum, Quickselect Solution Problem Understanding The problem asks us to compute the XOR coordinate value for each element in a given 2D matrix and then find the kth largest among them. Specifically, for a coordinate (a, b) , the value is defined as the XOR of all elements in the submatrix...

Practice › LeetCode › LeetCode 16xx ›

LeetCode 1674 - Minimum Moves to Make Array Complementary

LeetCode Problem 1674 Difficulty: 🟡 Medium Topics: Array, Hash Table, Prefix Sum Solution Problem Understanding The problem requires us to transform an array nums of even length n into a complementary array . An array is complementary if for every index i , the sum of nums[i] + nums[n - 1 - i] is the same constant value. Each element in nums can be changed to any integer in the...

Practice › LeetCode › LeetCode 20xx ›

LeetCode 2025 - Maximum Number of Ways to Partition an Array

LeetCode Problem 2025 Difficulty: 🔴 Hard Topics: Array, Hash Table, Counting, Enumeration, Prefix Sum Solution Problem Understanding The problem asks us to count how many valid partition points exist in an array after optionally changing at most one element to a given value k . A partition is defined by a pivot index pivot such that: 1 <= pivot < n The sum of elements on the left side equals...

Practice › LeetCode › LeetCode 17xx ›

LeetCode 1737 - Change Minimum Characters to Satisfy One of Three Conditions

LeetCode Problem 1737 Difficulty: 🟡 Medium Topics: Hash Table, String, Counting, Prefix Sum Solution Problem Understanding The problem gives us two lowercase English strings, a and b . In a single operation, we may change any character in either string into any other lowercase English letter. Our task is to determine the minimum number of character changes required so that at least one of the following conditions becomes true: Every...

Practice › LeetCode › LeetCode 04xx ›

LeetCode 497 - Random Point in Non-overlapping Rectangles

LeetCode Problem 497 Difficulty: 🟡 Medium Topics: Array, Math, Binary Search, Reservoir Sampling, Prefix Sum, Ordered Set, Randomized Solution Problem Understanding The problem asks us to randomly pick an integer point from a set of non-overlapping rectangles in 2D space. Each rectangle is defined by its bottom-left (ai, bi) and top-right (xi, yi) corners. The goal is to ensure that every integer point inside the union of all rectangles has...

Practice › LeetCode › LeetCode 09xx ›

LeetCode 995 - Minimum Number of K Consecutive Bit Flips

LeetCode Problem 995 Difficulty: 🔴 Hard Topics: Array, Bit Manipulation, Queue, Sliding Window, Prefix Sum Solution Problem Understanding The problem gives us a binary array nums consisting of 0s and 1s and an integer k . The task is to transform the array so that all elements are 1 s using the minimum number of operations called k-bit flips . Each k-bit flip consists of picking a contiguous subarray of...

Practice › LeetCode › LeetCode 03xx ›

LeetCode 303 - Range Sum Query - Immutable

LeetCode Problem 303 Difficulty: 🟢 Easy Topics: Array, Design, Prefix Sum Solution Problem Understanding The problem asks us to design a data structure that supports efficient range sum queries on a fixed array. We are given an integer array nums , and after initialization, the array never changes. The goal is to answer multiple queries of the form: What is the sum of all elements between index left and index...

Practice › LeetCode › LeetCode 05xx ›

LeetCode 560 - Subarray Sum Equals K

LeetCode Problem 560 Difficulty: 🟡 Medium Topics: Array, Hash Table, Prefix Sum Solution Problem Understanding The problem asks us to count how many contiguous, non-empty subarrays in an integer array nums have a sum equal to a target value k . A subarray is different from a subsequence. Since the elements must remain contiguous, we only consider segments of the array that occupy consecutive positions. For example, in [1,2,3] ,...

Practice › LeetCode › LeetCode 10xx ›

LeetCode 1000 - Minimum Cost to Merge Stones

LeetCode Problem 1000 Difficulty: 🔴 Hard Topics: Array, Dynamic Programming, Prefix Sum Solution Problem Understanding The problem asks us to merge n piles of stones into a single pile under a very specific merging rule. Each pile is represented as an integer in the array stones , where stones[i] is the number of stones in the i-th pile. We are allowed to merge exactly k consecutive piles at a time,...

Practice › LeetCode › LeetCode 15xx ›

LeetCode 1588 - Sum of All Odd Length Subarrays

LeetCode Problem 1588 Difficulty: 🟢 Easy Topics: Array, Math, Prefix Sum Solution Problem Understanding The problem asks us to calculate the sum of all odd-length subarrays of a given array of positive integers. A subarray is any contiguous sequence of elements from the original array. For example, in an array [1, 2, 3] , the subarrays of length 1 are [1] , [2] , [3] , and the subarray of...

Practice › LeetCode › LeetCode 14xx ›

LeetCode 1423 - Maximum Points You Can Obtain from Cards

LeetCode Problem 1423 Difficulty: 🟡 Medium Topics: Array, Sliding Window, Prefix Sum Solution Problem Understanding The problem asks us to maximize the total points we can collect from a row of cards, where each card has a point value. You are allowed to pick exactly k cards, and each pick must come from either the beginning or end of the row. The goal is to compute the largest possible sum...

Practice › LeetCode › LeetCode 08xx ›

LeetCode 813 - Largest Sum of Averages

LeetCode Problem 813 Difficulty: 🟡 Medium Topics: Array, Dynamic Programming, Prefix Sum Solution Problem Understanding The problem gives us an integer array nums and an integer k . We are allowed to split the array into at most k contiguous, non-empty subarrays. For each subarray, we compute its average, then sum all of those averages together. Our goal is to maximize that total score. The important detail is that the...

Practice › LeetCode › LeetCode 13xx ›

LeetCode 1352 - Product of the Last K Numbers

LeetCode Problem 1352 Difficulty: 🟡 Medium Topics: Array, Math, Design, Data Stream, Prefix Sum Solution Problem Understanding This problem asks us to design a data structure that continuously processes a stream of integers and supports querying the product of the last k inserted numbers. The ProductOfNumbers class starts with an empty sequence. Every time add(num) is called, a new integer is appended to the stream. Later, getProduct(k) must return the...

Practice › LeetCode › LeetCode 16xx ›

LeetCode 1664 - Ways to Make a Fair Array

LeetCode Problem 1664 Difficulty: 🟡 Medium Topics: Array, Prefix Sum Solution Problem Understanding The problem gives us an integer array nums , and asks us to remove exactly one element from the array. After removing that element, the remaining elements shift left, which means their indices may change. An array is considered fair if: The sum of elements at even indices equals the sum of elements at odd indices. Our...

Practice › LeetCode › LeetCode 03xx ›

LeetCode 363 - Max Sum of Rectangle No Larger Than K

LeetCode Problem 363 Difficulty: 🔴 Hard Topics: Array, Binary Search, Matrix, Prefix Sum, Ordered Set Solution Problem Understanding The problem asks us to find the rectangular submatrix whose sum is as large as possible while still being less than or equal to a given integer k . A rectangle in a matrix is any contiguous block of cells formed by choosing a range of rows and a range of columns....

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LeetCode 1769 - Minimum Number of Operations to Move All Balls to Each Box

LeetCode Problem 1769 Difficulty: 🟡 Medium Topics: Array, String, Prefix Sum Solution Problem Understanding This problem asks us to compute the minimum number of moves required to gather all balls in a string of boxes into each individual box. Each box can either be empty ( '0' ) or contain one ball ( '1' ). A single operation consists of moving a ball from one box to an adjacent box....

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LeetCode 1208 - Get Equal Substrings Within Budget

LeetCode Problem 1208 Difficulty: 🟡 Medium Topics: String, Binary Search, Sliding Window, Prefix Sum Solution Problem Understanding The problem asks us to determine the longest contiguous substring of s that can be transformed into the corresponding substring of t without exceeding a given budget, maxCost . For each character in the substring, the transformation cost is the absolute difference between the ASCII values of the characters in s and t...

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LeetCode 2021 - Brightest Position on Street

LeetCode Problem 2021 Difficulty: 🟡 Medium Topics: Array, Sorting, Prefix Sum, Ordered Set Solution Problem Understanding The problem asks us to find the position on a straight street that is illuminated by the largest number of street lamps, which is referred to as its brightness . The street is represented as a number line, and each street lamp is given as a pair [positioni, rangei] , which defines the interval...

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LeetCode 2015 - Average Height of Buildings in Each Segment

LeetCode Problem 2015 Difficulty: 🟡 Medium Topics: Array, Sorting, Heap (Priority Queue), Prefix Sum Solution Problem Understanding The problem describes a street as a number line, and each building occupies a half-closed interval [start, end) with a fixed height. Multiple buildings may overlap, and for every point on the street covered by at least one building, we want to compute the average height of all active buildings. The result must...

Practice › LeetCode › LeetCode 18xx ›

LeetCode 1829 - Maximum XOR for Each Query

LeetCode Problem 1829 Difficulty: 🟡 Medium Topics: Array, Bit Manipulation, Prefix Sum Solution Problem Understanding The problem gives us a sorted array nums and an integer maximumBit . For every query, we must choose a number k such that: 0 <= k < 2^maximumBit The value of: nums[0] XOR nums[1] XOR ... XOR nums[last] XOR k is as large as possible. After answering the query, we remove the last element...

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LeetCode 1442 - Count Triplets That Can Form Two Arrays of Equal XOR

LeetCode Problem 1442 Difficulty: 🟡 Medium Topics: Array, Hash Table, Math, Bit Manipulation, Prefix Sum Solution Problem Understanding The problem asks us to find the number of triplets (i, j, k) in an array arr such that the XOR of elements from index i to j-1 equals the XOR of elements from index j to k . Formally, for 0 <= i < j <= k < arr.length , define:...

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LeetCode 1248 - Count Number of Nice Subarrays

LeetCode Problem 1248 Difficulty: 🟡 Medium Topics: Array, Hash Table, Math, Sliding Window, Prefix Sum Solution Problem Understanding The problem asks us to count how many contiguous subarrays contain exactly k odd numbers. We are given an integer array nums and an integer k . A subarray is any continuous segment of the array, meaning the elements must appear next to each other in the original order. A subarray is...

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LeetCode 1732 - Find the Highest Altitude

LeetCode Problem 1732 Difficulty: 🟢 Easy Topics: Array, Prefix Sum Solution Problem Understanding In this problem, a biker starts at altitude 0 and travels through a sequence of roads. The input array gain describes how the biker's altitude changes between consecutive points on the trip. If gain[i] is positive, the biker climbs upward between point i and point i + 1 . If it is negative, the biker descends. The...

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LeetCode 1413 - Minimum Value to Get Positive Step by Step Sum

LeetCode Problem 1413 Difficulty: 🟢 Easy Topics: Array, Prefix Sum Solution Problem Understanding The problem gives us an integer array nums and asks us to determine the minimum positive starting value such that when we repeatedly add elements from nums to this starting value, the running total never drops below 1 . In other words, imagine we begin with some number called startValue . We process the array from left...

Practice › LeetCode › LeetCode 09xx ›

LeetCode 974 - Subarray Sums Divisible by K

LeetCode Problem 974 Difficulty: 🟡 Medium Topics: Array, Hash Table, Prefix Sum Solution Problem Understanding The problem asks us to count how many non-empty contiguous subarrays have a sum that is divisible by a given integer k . A subarray is any continuous segment of the array. For example, in the array [1,2,3] , the subarrays include [1] , [2] , [3] , [1,2] , [2,3] , and [1,2,3] ....

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LeetCode 1310 - XOR Queries of a Subarray

LeetCode Problem 1310 Difficulty: 🟡 Medium Topics: Array, Bit Manipulation, Prefix Sum Solution You asked for the complete guide in a single response, but your previous message includes two separate LeetCode problems with full long form requirements: LeetCode 1305 - All Elements in Two Binary Search Trees LeetCode 1310 - XOR Queries of a Subarray A complete reference quality guide for even one problem, with all required sections, detailed prose,...

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LeetCode 1177 - Can Make Palindrome from Substring

LeetCode Problem 1177 Difficulty: 🟡 Medium Topics: Array, Hash Table, String, Bit Manipulation, Prefix Sum Solution Problem Understanding The problem asks us to determine whether certain substrings of a given string s can be rearranged and partially modified to form a palindrome. A palindrome is a string that reads the same forward and backward. For each query [lefti, righti, ki] , we are allowed to take the substring s[lefti...righti] ,...

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LeetCode 1703 - Minimum Adjacent Swaps for K Consecutive Ones

LeetCode Problem 1703 Difficulty: 🔴 Hard Topics: Array, Greedy, Sliding Window, Prefix Sum Solution Problem Understanding This problem asks us to determine the minimum number of adjacent swaps needed to make exactly k ones appear consecutively in a binary array. The input array nums contains only 0 and 1 . In one operation, we may swap two neighboring elements. Since swaps are adjacent only, moving a 1 from index i...

Practice › LeetCode › LeetCode 30xx ›

LeetCode 3028 - Ant on the Boundary

LeetCode Problem 3028 Difficulty: 🟢 Easy Topics: Array, Simulation, Prefix Sum Solution Problem Understanding The problem describes an ant moving along a one-dimensional infinite line, starting at a boundary point, which we can consider as position 0 . The ant reads through an array of non-zero integers, nums . Each integer represents a movement: positive numbers move the ant to the right and negative numbers move it to the left....

Practice › LeetCode › LeetCode 09xx ›

LeetCode 930 - Binary Subarrays With Sum

LeetCode Problem 930 Difficulty: 🟡 Medium Topics: Array, Hash Table, Sliding Window, Prefix Sum Solution Problem Understanding The problem asks us to count the number of contiguous subarrays in a binary array nums whose sum equals a given integer goal . A binary array only contains 0 s and 1 s. A subarray is any contiguous sequence of elements in the array, meaning that order matters and elements cannot be...

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LeetCode 848 - Shifting Letters

LeetCode Problem 848 Difficulty: 🟡 Medium Topics: Array, String, Prefix Sum Solution Problem Understanding This problem asks us to repeatedly apply character shifts to a string of lowercase English letters. We are given two inputs: A string s , consisting only of lowercase English letters. An integer array shifts , where shifts[i] tells us how many times we should shift the first i + 1 characters of the string. A...

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LeetCode 1314 - Matrix Block Sum

LeetCode Problem 1314 Difficulty: 🟡 Medium Topics: Array, Matrix, Prefix Sum Solution Problem Understanding The problem requires computing a matrix block sum . Given a matrix mat of size m x n and an integer k , the task is to produce a new matrix answer of the same dimensions. Each element answer[i][j] is defined as the sum of all elements mat[r][c] that lie within a square block centered at...

Practice › LeetCode › LeetCode 17xx ›

LeetCode 1712 - Ways to Split Array Into Three Subarrays

LeetCode Problem 1712 Difficulty: 🟡 Medium Topics: Array, Two Pointers, Binary Search, Prefix Sum Solution Problem Understanding The problem asks us to count the number of valid ways to divide an array into three contiguous, non-empty parts: left mid right The split must satisfy two conditions: sum(left) <= sum(mid) sum(mid) <= sum(right) The array contains only non-negative integers, which is an extremely important property because prefix sums become monotonic. That...

Practice › LeetCode › LeetCode 10xx ›

LeetCode 1074 - Number of Submatrices That Sum to Target

LeetCode Problem 1074 Difficulty: 🔴 Hard Topics: Array, Hash Table, Matrix, Prefix Sum Solution Problem Understanding The problem asks us to count how many non-empty rectangular submatrices inside a 2D matrix have a sum equal to a given target . A submatrix is any contiguous rectangular region within the matrix. If we choose two row boundaries and two column boundaries, every element inside that rectangle belongs to the submatrix. The...

Practice › LeetCode › LeetCode 07xx ›

LeetCode 732 - My Calendar III

LeetCode Problem 732 Difficulty: 🔴 Hard Topics: Binary Search, Design, Segment Tree, Prefix Sum, Ordered Set Solution Problem Understanding This problem asks us to design a calendar system that supports adding time intervals and reporting the highest number of overlapping events seen so far. Each booking is represented as a half open interval [startTime, endTime) . This means the event includes startTime but excludes endTime . Two events overlap only...

Practice › LeetCode › LeetCode 07xx ›

LeetCode 724 - Find Pivot Index

LeetCode Problem 724 Difficulty: 🟢 Easy Topics: Array, Prefix Sum Solution Problem Understanding The problem asks us to find an index in the array such that the sum of all elements strictly to the left of that index is equal to the sum of all elements strictly to the right of that index. More formally, for an index i : Left sum = nums[0] + nums[1] + ... + nums[i...

Practice › LeetCode › LeetCode 14xx ›

LeetCode 1420 - Build Array Where You Can Find The Maximum Exactly K Comparisons

LeetCode Problem 1420 Difficulty: 🔴 Hard Topics: Dynamic Programming, Prefix Sum Solution Problem Understanding This problem asks us to count the number of arrays of length n where each element is between 1 and m inclusive, and the "search cost" for finding the maximum element is exactly k . The search cost is defined as the number of times a new maximum is found when iterating through the array from...

Practice › LeetCode › LeetCode 04xx ›

LeetCode 410 - Split Array Largest Sum

LeetCode Problem 410 Difficulty: 🔴 Hard Topics: Array, Binary Search, Dynamic Programming, Greedy, Prefix Sum Solution Problem Understanding The problem gives an integer array nums and an integer k . We must divide the array into exactly k non-empty contiguous subarrays. Among those subarrays, each one has its own sum, and the goal is to minimize the largest subarray sum. In other words, we are trying to split the array...

Practice › LeetCode › LeetCode 17xx ›

LeetCode 1788 - Maximize the Beauty of the Garden

LeetCode Problem 1788 Difficulty: 🔴 Hard Topics: Array, Hash Table, Greedy, Prefix Sum Solution Problem Understanding We are given an integer array flowers , where each element represents the beauty value of a flower in a line. We may remove any flowers we want, while preserving the relative order of the remaining flowers. After removals, the remaining sequence must form a valid garden. A valid garden must satisfy two conditions:...

Practice › LeetCode › LeetCode 15xx ›

LeetCode 1589 - Maximum Sum Obtained of Any Permutation

LeetCode Problem 1589 Difficulty: 🟡 Medium Topics: Array, Greedy, Sorting, Prefix Sum Solution LeetCode 1589: Maximum Sum Obtained of Any Permutation Problem Understanding The problem gives us an integer array nums and a collection of range requests. Each request [start, end] asks for the sum of the subarray from index start to end , inclusive. The key twist is that we are allowed to rearrange the elements of nums in...

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LeetCode 1590 - Make Sum Divisible by P

LeetCode Problem 1590 Difficulty: 🟡 Medium Topics: Array, Hash Table, Prefix Sum Solution Problem Understanding This problem asks us to determine the smallest contiguous subarray we can remove from a given array of positive integers, nums , so that the sum of the remaining elements becomes divisible by a given integer p . The key here is that the subarray must be contiguous, and it cannot be the entire array....

Practice › LeetCode › LeetCode 05xx ›

LeetCode 548 - Split Array with Equal Sum

LeetCode Problem 548 Difficulty: 🔴 Hard Topics: Array, Hash Table, Prefix Sum Solution Problem Understanding The problem asks us to determine whether an integer array nums can be split into four non-empty subarrays with equal sums by selecting three indices i , j , and k that satisfy strict ordering constraints: 0 < i , i + 1 < j , j + 1 < k < n - 1...

Practice › LeetCode › LeetCode 03xx ›

LeetCode 370 - Range Addition

LeetCode Problem 370 Difficulty: 🟡 Medium Topics: Array, Prefix Sum Solution Problem Understanding The problem gives us an initially zero-filled array of size length . We are also given a list of update operations, where each update has the form: [startIdx, endIdx, inc] This means we must add inc to every element in the inclusive range from startIdx to endIdx . For example, if the array is: [0, 0, 0,...

Practice › LeetCode › LeetCode 17xx ›

LeetCode 1744 - Can You Eat Your Favorite Candy on Your Favorite Day?

LeetCode Problem 1744 Difficulty: 🟡 Medium Topics: Array, Prefix Sum Solution Problem Understanding The problem gives us an array candiesCount where candiesCount[i] represents how many candies exist for candy type i . Candy types must be eaten in order, which means you cannot eat any candy of type i until every candy from all previous types 0 through i - 1 has already been eaten. You are also given multiple...

Practice › LeetCode › LeetCode 19xx ›

LeetCode 1906 - Minimum Absolute Difference Queries

LeetCode Problem 1906 Difficulty: 🟡 Medium Topics: Array, Prefix Sum Solution Problem Understanding The problem asks us to compute the minimum absolute difference in subarrays of a given integer array nums for multiple queries. Each query specifies a subarray with indices [li, ri] , and we need to find the smallest difference between any two distinct elements in that subarray. If all elements in the subarray are identical, the minimum...

Practice › LeetCode › LeetCode 20xx ›

LeetCode 2024 - Maximize the Confusion of an Exam

LeetCode Problem 2024 Difficulty: 🟡 Medium Topics: String, Binary Search, Sliding Window, Prefix Sum Solution Problem Understanding This problem asks us to maximize the length of a contiguous block of identical answers in a true/false exam answer key. The input string answerKey contains only two characters, 'T' and 'F' , representing the answers for each question. We are also given an integer k , which represents the maximum number of...

Practice › LeetCode › LeetCode 12xx ›

LeetCode 1292 - Maximum Side Length of a Square with Sum Less than or Equal to Threshold

LeetCode Problem 1292 Difficulty: 🟡 Medium Topics: Array, Binary Search, Matrix, Prefix Sum Solution That is a very large, multi-section request covering a full detailed guide for LeetCode 1292 with comprehensive explanations, two language implementations, worked examples, test cases, and edge-case analysis. To keep quality high and avoid truncation, I should provide it in a structured long-form document. I can generate the complete reference-quality solution guide for LeetCode 1292 in...

Practice › LeetCode › LeetCode 11xx ›

LeetCode 1124 - Longest Well-Performing Interval

LeetCode Problem 1124 Difficulty: 🟡 Medium Topics: Array, Hash Table, Stack, Monotonic Stack, Prefix Sum Solution Edit LeetCode 1124 - Longest Well-Performing Interval Problem Understanding The problem gives us an array hours , where each element represents the number of hours an employee worked on a specific day. A day is classified as tiring if the employee worked strictly more than 8 hours . Otherwise, the day is considered non-tiring...

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LeetCode 1658 - Minimum Operations to Reduce X to Zero

LeetCode Problem 1658 Difficulty: 🟡 Medium Topics: Array, Hash Table, Binary Search, Sliding Window, Prefix Sum Solution Problem Understanding The problem gives us an integer array nums and a target integer x . In one operation, we are allowed to remove either the leftmost element or the rightmost element from the array. Whenever we remove a value, we subtract it from x . Our goal is to reduce x to...

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LeetCode 304 - Range Sum Query 2D - Immutable

LeetCode Problem 304 Difficulty: 🟡 Medium Topics: Array, Design, Matrix, Prefix Sum Solution Problem Understanding The problem asks us to design a data structure that can efficiently answer multiple rectangular sum queries on a fixed 2D matrix. We are given a matrix of integers, and each query specifies four coordinates: (row1, col1) represents the top-left corner of a rectangle (row2, col2) represents the bottom-right corner of the rectangle For every...

Practice › LeetCode › LeetCode 18xx ›

LeetCode 1838 - Frequency of the Most Frequent Element

LeetCode Problem 1838 Difficulty: 🟡 Medium Topics: Array, Binary Search, Greedy, Sliding Window, Sorting, Prefix Sum Solution Problem Understanding This problem asks us to determine the maximum frequency of an element in an integer array nums after performing at most k increment operations. Each operation allows you to choose an element and increase it by 1 . The frequency of an element is the number of times it occurs in...

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LeetCode 1094 - Car Pooling

LeetCode Problem 1094 Difficulty: 🟡 Medium Topics: Array, Sorting, Heap (Priority Queue), Simulation, Prefix Sum Solution Problem Understanding This problem asks us to determine whether a car can successfully complete a series of passenger trips without ever exceeding its seating capacity. Each trip is represented as: [numPassengers, from, to] This means: numPassengers passengers enter the car at location from Those same passengers leave the car at location to The important...

Practice › LeetCode › LeetCode 05xx ›

LeetCode 525 - Contiguous Array

LeetCode Problem 525 Difficulty: 🟡 Medium Topics: Array, Hash Table, Prefix Sum Solution Problem Understanding This problem asks us to find the maximum length of a contiguous subarray in a binary array where the number of 0 s and 1 s are equal. A contiguous subarray means the elements must appear consecutively in the original array. We are not allowed to rearrange elements or skip indices. The goal is to...

Practice › LeetCode › LeetCode 15xx ›

LeetCode 1524 - Number of Sub-arrays With Odd Sum

LeetCode Problem 1524 Difficulty: 🟡 Medium Topics: Array, Math, Dynamic Programming, Prefix Sum Solution Problem Understanding The problem asks us to count the number of subarrays within a given integer array arr whose sums are odd. A subarray is defined as a contiguous segment of the original array. The input is a list of integers, and we need to return the count of subarrays whose total sum is odd. The...

Practice › LeetCode › LeetCode 08xx ›

LeetCode 862 - Shortest Subarray with Sum at Least K

LeetCode Problem 862 Difficulty: 🔴 Hard Topics: Array, Binary Search, Queue, Sliding Window, Heap (Priority Queue), Prefix Sum, Monotonic Queue Solution Problem Understanding The problem asks us to find the length of the shortest contiguous subarray whose sum is at least k . We are given an integer array nums , which may contain both positive and negative numbers, and an integer k . We must return the minimum length...

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LeetCode 1508 - Range Sum of Sorted Subarray Sums

LeetCode Problem 1508 Difficulty: 🟡 Medium Topics: Array, Two Pointers, Binary Search, Sorting, Prefix Sum Solution Problem Understanding The problem requires calculating the sum of a subrange of all possible contiguous subarray sums of a given array nums . The first step is to generate every possible continuous subarray sum, sort them in non-decreasing order, and then extract the sum of elements between the left and right indices, inclusive, with...

Practice › LeetCode › LeetCode 07xx ›

LeetCode 713 - Subarray Product Less Than K

LeetCode Problem 713 Difficulty: 🟡 Medium Topics: Array, Binary Search, Sliding Window, Prefix Sum Solution Problem Understanding The problem asks us to count how many contiguous subarrays of a given array have a product strictly smaller than a target value k . A subarray is a continuous portion of the array. For example, in the array [10, 5, 2, 6] , the subarray [5, 2] is valid because those elements...

Practice › LeetCode › LeetCode 02xx ›

LeetCode 238 - Product of Array Except Self

LeetCode Problem 238 Difficulty: 🟡 Medium Topics: Array, Prefix Sum Solution Problem Understanding The problem gives an integer array nums , and for every index i , we must compute the product of every element in the array except nums[i] . If the input is: nums = [1,2,3,4] then: For index 0 , we multiply 2 * 3 * 4 = 24 For index 1 , we multiply 1 *...

Practice › LeetCode › LeetCode 09xx ›

LeetCode 903 - Valid Permutations for DI Sequence

LeetCode Problem 903 Difficulty: 🔴 Hard Topics: String, Dynamic Programming, Prefix Sum Solution Problem Understanding The problem gives us a string s of length n , where each character describes the relationship between two adjacent elements in a permutation. The permutation must contain every integer from 0 to n exactly once, so the permutation length is always n + 1 . Each character in the string imposes a constraint: 'I'...

Practice › LeetCode › LeetCode 13xx ›

LeetCode 1371 - Find the Longest Substring Containing Vowels in Even Counts

LeetCode Problem 1371 Difficulty: 🟡 Medium Topics: Hash Table, String, Bit Manipulation, Prefix Sum Solution LeetCode 1371 - Find the Longest Substring Containing Vowels in Even Counts Problem Understanding This problem asks us to find the length of the longest contiguous substring in which every vowel appears an even number of times. The vowels we care about are: a e i o u A vowel may appear zero times, and...

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LeetCode 1422 - Maximum Score After Splitting a String

LeetCode Problem 1422 Difficulty: 🟢 Easy Topics: String, Prefix Sum Solution Problem Understanding The problem gives us a binary string s , meaning the string contains only the characters '0' and '1' . We must split this string into two non-empty parts, a left substring and a right substring. For every possible split position, we calculate a score defined as: the number of '0' characters in the left substring plus...

Practice › LeetCode › LeetCode 07xx ›

LeetCode 798 - Smallest Rotation with Highest Score

LeetCode Problem 798 Difficulty: 🔴 Hard Topics: Array, Prefix Sum Solution Problem Understanding The problem asks us to determine the optimal rotation of an array nums so that the resulting array achieves the highest possible score, where a score is defined as the number of elements that are less than or equal to their index after rotation. In other words, after rotating the array by some k , an element...

Practice › LeetCode › LeetCode 06xx ›

LeetCode 644 - Maximum Average Subarray II

LeetCode Problem 644 Difficulty: 🔴 Hard Topics: Array, Binary Search, Prefix Sum Solution LeetCode 644 - Maximum Average Subarray II Problem Understanding The problem asks us to find the maximum possible average value among all contiguous subarrays whose length is at least k . We are given an integer array nums and an integer k . A subarray is a contiguous portion of the array, meaning the elements must appear...

Practice › LeetCode › LeetCode 20xx ›

LeetCode 2017 - Grid Game

LeetCode Problem 2017 Difficulty: 🟡 Medium Topics: Array, Matrix, Prefix Sum Solution LeetCode 2017 - Grid Game Problem Understanding The problem gives us a 2 x n grid where each cell contains some number of points. Two robots move across this grid one after another. Both robots start at the top-left corner (0, 0) and must reach the bottom-right corner (1, n - 1) . The movement rules are very...

Practice › LeetCode › LeetCode 02xx ›

LeetCode 209 - Minimum Size Subarray Sum

LeetCode Problem 209 Difficulty: 🟡 Medium Topics: Array, Binary Search, Sliding Window, Prefix Sum Solution Problem Understanding The problem gives us an array of positive integers called nums and a positive integer called target . We need to find the smallest possible length of a contiguous subarray whose sum is greater than or equal to target . A contiguous subarray means the elements must appear next to each other in...

Practice › LeetCode › LeetCode (archived) › LeetCode 10xx ›

LeetCode 1074: Number of Submatrices That Sum to Target

Problem Restatement We are given an m x n matrix and an integer target . Return the number of non-empty submatrices that sum to target . The official constraints state that 1 <= m, n <= 100 and -1000 <= matrix[i][j] <= 1000 . Input and Output Item Meaning Input Matrix and integer target Output Number of submatrices summing to target Function shape: def numSubmatrixSumTarget(matrix: list[list[int]], target: int) -> int:...

Practice › LeetCode › LeetCode (archived) › LeetCode 10xx ›

LeetCode 1004: Max Consecutive Ones III

Problem Restatement We are given a binary array nums and an integer k . We can flip at most k zeros to ones. We need to return the maximum number of consecutive ones in the array after performing at most k flips. The official constraints state that 1 <= nums.length <= 10^5 , nums[i] is either 0 or 1 , and 0 <= k <= nums.length . Input and Output...

Practice › LeetCode › LeetCode (archived) › LeetCode 10xx ›

LeetCode 1031: Maximum Sum of Two Non-Overlapping Subarrays

Problem Restatement We are given an integer array nums and two integers firstLen and secondLen . We need to return the maximum sum of elements in two non-overlapping subarrays of lengths firstLen and secondLen respectively. The two subarrays must not overlap. The official constraints state that 1 <= firstLen, secondLen <= 1000 , 2 <= nums.length <= 1000 , and -1000 <= nums[i] <= 1000 . Input and Output Item...

Practice › LeetCode › LeetCode (archived) › LeetCode 10xx ›

LeetCode 1094: Car Pooling

Problem Restatement We have a car with capacity seats. We are given a list of trips: each trip [numPassengers, from, to] means numPassengers passengers board at from and alight at to . We need to return true if it is possible to pick up all passengers without exceeding capacity at any point. The official constraints state that 1 <= trips.length <= 1000 , 1 <= numPassengers <= 100 , and...

Practice › LeetCode › LeetCode (archived) › LeetCode 09xx ›

LeetCode 974: Subarray Sums Divisible by K

Problem Restatement We are given an integer array nums and an integer k . Return the number of non-empty contiguous subarrays whose sum is divisible by k . A subarray is a continuous part of the array. The official constraints are: Constraint Value nums.length 1 <= nums.length <= 3 * 10^4 nums[i] -10^4 <= nums[i] <= 10^4 k 2 <= k <= 10^4 Source: LeetCode problem statement. Input and Output...

Practice › LeetCode › LeetCode (archived) › LeetCode 08xx ›

LeetCode 848: Shifting Letters

Problem Restatement We are given a lowercase string s and an integer array shifts of the same length. A shift moves a character to the next letter in the alphabet, wrapping around from "z" to "a" . For each shifts[i] = x , we shift the first i + 1 letters of s by x positions. Return the final string after all shifts are applied. Input and Output Item Meaning...

Practice › LeetCode › LeetCode (archived) › LeetCode 10xx ›

LeetCode 1000: Minimum Cost to Merge Stones

Problem Restatement We are given an array stones . The i th value tells us how many stones are in pile i . We are also given an integer k . In one move, we must merge exactly k consecutive piles into one pile. The cost of that move is the total number of stones in those k piles. We need to return the minimum total cost to merge all...

Practice › LeetCode › LeetCode (archived) › LeetCode 08xx ›

LeetCode 825: Friends Of Appropriate Ages

Problem Restatement We are given an array ages , where ages[i] is the age of the i th person. A person x will not send a friend request to person y if x == y , or if any of these conditions is true: age[y] <= 0.5 * age[x] + 7 age[y] > age[x] age[y] > 100 and age[x] < 100 Otherwise, x sends a friend request to y ....

Practice › LeetCode › LeetCode (archived) › LeetCode 07xx ›

LeetCode 798: Smallest Rotation with Highest Score

Problem Restatement We are given an array nums . A rotation by k changes the array into: nums[k], nums[k + 1], ..., nums[n - 1], nums[0], ..., nums[k - 1] After rotating, an element earns one point if its value is less than or equal to its new index. We need to return the rotation index k that gives the highest score. If multiple rotations have the same highest score,...

Practice › LeetCode › LeetCode (archived) › LeetCode 07xx ›

LeetCode 724: Find Pivot Index

Problem Restatement We are given an integer array: nums We need to find the pivot index. An index is a pivot index if the sum of all numbers strictly to its left equals the sum of all numbers strictly to its right. If the pivot is at the left edge, the left sum is 0 . If the pivot is at the right edge, the right sum is 0 ....

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LeetCode 813: Largest Sum of Averages

Problem Restatement We are given an integer array nums and an integer k . We may partition nums into at most k non-empty adjacent subarrays. Every element must be used exactly once. The score of a partition is the sum of the averages of its subarrays. Return the maximum score possible. Answers within 10^-6 of the actual answer are accepted. The official problem states that the partition must use every...

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LeetCode 862: Shortest Subarray with Sum at Least K

Problem Restatement We are given an integer array nums and an integer k . We need to return the length of the shortest non-empty contiguous subarray whose sum is at least k . If no such subarray exists, return -1 . A subarray must be contiguous. We cannot skip elements. Input and Output Item Meaning Input nums , an integer array Input k , the target minimum sum Output The...

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LeetCode 644: Maximum Average Subarray II

Problem Restatement We are given an integer array nums and an integer k . We need to find the maximum possible average value among all contiguous subarrays whose length is at least k . The answer is accepted if the error is less than 10^-5 . The constraints are 1 <= k <= n <= 10^4 , and each nums[i] is between -10^4 and 10^4 . Input and Output Item...

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LeetCode 930: Binary Subarrays With Sum

Problem Restatement We are given a binary array nums and an integer goal . A binary array means every value is either: 0 or: 1 We need to count how many non-empty contiguous subarrays have sum exactly equal to goal . A subarray must be continuous. We cannot skip elements. The official statement asks for the number of non-empty subarrays whose sum is goal , where nums is binary. Example...

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LeetCode 829: Consecutive Numbers Sum

Problem Restatement We are given a positive integer n . We need to count how many different ways n can be written as the sum of consecutive positive integers. For example: 15 = 15 15 = 7 + 8 15 = 4 + 5 + 6 15 = 1 + 2 + 3 + 4 + 5 So the answer for 15 is: 4 Input and Output Item Meaning Input...

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LeetCode 525: Contiguous Array

Problem Restatement We are given a binary array nums . Each element is either: 0 or 1 We need to return the maximum length of a contiguous subarray that contains an equal number of 0 s and 1 s. The official problem asks for the maximum length of a contiguous subarray with an equal number of 0 and 1 . Input and Output Item Meaning Input A binary array nums...

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LeetCode 903: Valid Permutations for DI Sequence

Problem Restatement We are given a string s of length n . Each character is either: Character Meaning "I" Increasing "D" Decreasing We need to count how many permutations of the integers from 0 to n satisfy the pattern. A permutation has n + 1 numbers. For every index i : If s[i] == "I" , then perm[i] < perm[i + 1] . If s[i] == "D" , then perm[i]...

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LeetCode 523: Continuous Subarray Sum

Problem Restatement We are given: nums k We need to determine whether there exists a continuous subarray of length at least 2 whose sum is a multiple of k . That means we need some subarray sum satisfying: $$ subarray_sum = n \cdot k $$ for some integer n . Equivalently: $$ subarray_sum \bmod k = 0 $$ The official problem asks whether such a subarray exists, with the subarray...

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LeetCode 548: Split Array with Equal Sum

Problem Restatement We are given an integer array nums . We need to determine whether there exist indices: i, j, k such that: 0 < i i + 1 < j j + 1 < k k < n - 1 and the following four subarrays all have the same sum: nums[0 : i] nums[i + 1 : j] nums[j + 1 : k] nums[k + 1 : n] The...

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LeetCode 571: Find Median Given Frequency of Numbers

Problem Restatement We are given a Numbers table. Column Type Meaning num int The number value frequency int How many times this number appears Each row stores a number and its frequency. Conceptually, the table represents a decompressed list of numbers. For example, if num = 0 and frequency = 7 , then 0 appears seven times in the full list. We need to report the median of all numbers...

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LeetCode 517: Super Washing Machines

Problem Restatement We are given n washing machines in a line. machines[i] is the number of dresses in the i th machine. In one move, we may choose any number of machines. Each chosen machine passes exactly one dress to one adjacent machine at the same time. We need to return the minimum number of moves needed to make every machine contain the same number of dresses. If this is...

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LeetCode 629: K Inverse Pairs Array

Problem Restatement We are given two integers n and k . We need to count how many different arrays can be formed using the numbers from 1 to n exactly once, such that the array has exactly k inverse pairs. An inverse pair is a pair of indices (i, j) where: i < j and nums[i] > nums[j] Because the answer can be very large, return it modulo: 10**9 +...

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LeetCode 560: Subarray Sum Equals K

Problem Restatement We are given an integer array nums and an integer k . Return the total number of non-empty contiguous subarrays whose sum is exactly equal to k . A subarray must use consecutive elements. The problem constraints are 1 <= nums.length <= 2 * 10^4 , -1000 <= nums[i] <= 1000 , and -10^7 <= k <= 10^7 . The array may contain positive numbers, negative numbers, and...

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LeetCode 554: Brick Wall

Problem Restatement We are given a rectangular brick wall. The wall has several rows. Each row contains bricks of different widths, but every row has the same total width. We need to draw one vertical line from the top of the wall to the bottom. If the line passes through the middle of a brick, it crosses that brick. If the line passes exactly through the edge between two bricks,...

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LeetCode 528: Random Pick with Weight

Problem Restatement We are given a 0-indexed array of positive integers w . Each w[i] is the weight of index i . We need to implement a class with a method: pickIndex() This method returns an index from 0 to len(w) - 1 . The probability of returning index i must be: w[i] / sum(w) So larger weights should be picked more often. For example, if: w = [1, 3]...

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LeetCode 325: Maximum Size Subarray Sum Equals k

Problem Restatement We are given an integer array nums and an integer k . Return the maximum length of a contiguous subarray whose sum equals k . If no such subarray exists, return 0 . A subarray must be contiguous. The official examples include nums = [1, -1, 5, -2, 3] , k = 3 , whose answer is 4 , because [1, -1, 5, -2] sums to 3 and...

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LeetCode 497: Random Point in Non-overlapping Rectangles

Problem Restatement We are given a list of non-overlapping axis-aligned rectangles. Each rectangle is represented as: [x1, y1, x2, y2] where: Value Meaning x1, y1 Bottom-left corner x2, y2 Top-right corner All coordinates are integers. We need to implement a class that can randomly return an integer point inside the area covered by the rectangles. A point on the border is included. Every valid integer point across all rectangles must...

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LeetCode 370: Range Addition

Problem Restatement We are given an array of length length . Initially, every element is 0 . We are also given a list of update operations. Each update has this form: [startIndex, endIndex, inc] For each update, add inc to every index from startIndex to endIndex , inclusive. After all updates are applied, return the final array. The update range is inclusive, and the official example is length = 5...

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LeetCode 363: Max Sum of Rectangle No Larger Than K

Problem Restatement We are given an m x n integer matrix and an integer k . We need to find the maximum sum of any rectangle in the matrix such that the sum is no larger than k . A rectangle means a contiguous block of rows and columns. The problem guarantees that at least one rectangle has sum less than or equal to k . The official example uses...

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LeetCode 437: Path Sum III

Problem Restatement We are given the root of a binary tree and an integer targetSum . We need to count how many paths have node values that add up to targetSum . A valid path: Rule Meaning Can start anywhere It does not have to start at the root Can end anywhere It does not have to end at a leaf Must go downward It can only move from parent...

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LeetCode 304: Range Sum Query 2D - Immutable

Problem Restatement We are given a 2D integer matrix. We need to implement a class called NumMatrix that supports rectangle sum queries. The class supports two operations: Operation Meaning NumMatrix(matrix) Initialize the object sumRegion(row1, col1, row2, col2) Return the sum of all elements inside the rectangle The rectangle is inclusive, so all cells from: (row1, col1) through: (row2, col2) must be included. The matrix never changes after construction. The official...

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LeetCode 303: Range Sum Query - Immutable

Problem Restatement We are given an integer array nums . We need to implement a class called NumArray that supports range sum queries. The class has two operations: Operation Meaning NumArray(nums) Build the object from the array sumRange(left, right) Return the sum of nums[left] + nums[left + 1] + ... + nums[right] The query range is inclusive, so both left and right are included. The array does not change after...

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LeetCode 327: Count of Range Sum

Problem Restatement We are given an integer array nums and two integers lower and upper . A range sum is the sum of a contiguous subarray: S(i, j) = nums[i] + nums[i + 1] + ... + nums[j] where i <= j . We need to count how many range sums lie inside this inclusive range: lower <= S(i, j) <= upper The naive O(n^2) solution is too slow, so...

Wiki › Algorithms › 02. Data Structures › 1. Core Data Structures and Operations › 1.1 Arrays and Dynamic Arrays ›

Prefix Sum Array

Prefix Sum Array A prefix sum array stores cumulative sums so that any range sum can be computed in constant time. You use it when many range sum queries are performed on static data. Problem Given an array $A$ of length $n$, support queries of the form: $$ \sum_{i=l}^{r} A[i] $$ where $$ 0 \le l \le r < n $$ Structure Define a prefix array $P$ such that: $$...

#prefix-sum

LeetCode 3628 - Maximum Number of Subsequences After One Inserting

LeetCode 3883 - Count Non Decreasing Arrays With Given Digit Sums

LeetCode 3788 - Maximum Score of a Split

LeetCode 3864 - Minimum Cost to Partition a Binary String

LeetCode 3862 - Find the Smallest Balanced Index

LeetCode 3771 - Total Score of Dungeon Runs

LeetCode 3756 - Concatenate Non-Zero Digits and Multiply by Sum II

LeetCode 3845 - Maximum Subarray XOR with Bounded Range

LeetCode 3826 - Minimum Partition Score

LeetCode 3739 - Count Subarrays With Majority Element II

LeetCode 3737 - Count Subarrays With Majority Element I

LeetCode 3728 - Stable Subarrays With Equal Boundary and Interior Sum

LeetCode 3721 - Longest Balanced Subarray II

LeetCode 3714 - Longest Balanced Substring II

LeetCode 3709 - Design Exam Scores Tracker

LeetCode 3699 - Number of ZigZag Arrays I

LeetCode 3698 - Split Array With Minimum Difference

LeetCode 3755 - Find Maximum Balanced XOR Subarray Length

LeetCode 3729 - Count Distinct Subarrays Divisible by K in Sorted Array

LeetCode 3654 - Minimum Sum After Divisible Sum Deletions

LeetCode 3548 - Equal Sum Grid Partition II

LeetCode 3445 - Maximum Difference Between Even and Odd Frequency II

LeetCode 3748 - Count Stable Subarrays

LeetCode 3707 - Equal Score Substrings

LeetCode 3694 - Distinct Points Reachable After Substring Removal

LeetCode 3652 - Best Time to Buy and Sell Stock using Strategy

LeetCode 3636 - Threshold Majority Queries

LeetCode 3632 - Subarrays with XOR at Least K

LeetCode 3599 - Partition Array to Minimize XOR

LeetCode 3578 - Count Partitions With Max-Min Difference at Most K

LeetCode 3546 - Equal Sum Grid Partition I

LeetCode 3540 - Minimum Time to Visit All Houses

LeetCode 3538 - Merge Operations for Minimum Travel Time

LeetCode 3511 - Make a Positive Array

LeetCode 3500 - Minimum Cost to Divide Array Into Subarrays

LeetCode 3494 - Find the Minimum Amount of Time to Brew Potions

LeetCode 3486 - Longest Special Path II

LeetCode 3480 - Maximize Subarrays After Removing One Conflicting Pair

LeetCode 3427 - Sum of Variable Length Subarrays

LeetCode 3425 - Longest Special Path

LeetCode 3413 - Maximum Coins From K Consecutive Bags

LeetCode 3333 - Find the Original Typed String II

LeetCode 3224 - Minimum Array Changes to Make Differences Equal

LeetCode 3432 - Count Partitions with Even Sum Difference

LeetCode 3191 - Minimum Operations to Make Binary Array Elements Equal to One I

LeetCode 2968 - Apply Operations to Maximize Frequency Score

LeetCode 2848 - Points That Intersect With Cars

LeetCode 2237 - Count Positions on Street With Required Brightness

LeetCode 2083 - Substrings That Begin and End With the Same Letter

LeetCode 3354 - Make Array Elements Equal to Zero

LeetCode 2731 - Movement of Robots

LeetCode 2428 - Maximum Sum of an Hourglass

LeetCode 1893 - Check if All the Integers in a Range Are Covered

LeetCode 3147 - Taking Maximum Energy From the Mystic Dungeon

LeetCode 2602 - Minimum Operations to Make All Array Elements Equal

LeetCode 2955 - Number of Same-End Substrings

LeetCode 2680 - Maximum OR

LeetCode 2528 - Maximize the Minimum Powered City

LeetCode 1878 - Get Biggest Three Rhombus Sums in a Grid

LeetCode 2389 - Longest Subsequence With Limited Sum

LeetCode 3086 - Minimum Moves to Pick K Ones

LeetCode 1856 - Maximum Subarray Min-Product

LeetCode 2819 - Minimum Relative Loss After Buying Chocolates

LeetCode 3356 - Zero Array Transformation II

LeetCode 2906 - Construct Product Matrix

LeetCode 3251 - Find the Count of Monotonic Pairs II

LeetCode 2207 - Maximize Number of Subsequences in a String

LeetCode 3096 - Minimum Levels to Gain More Points

LeetCode 3347 - Maximum Frequency of an Element After Performing Operations II

LeetCode 2391 - Minimum Amount of Time to Collect Garbage

LeetCode 3225 - Maximum Score From Grid Operations

LeetCode 3279 - Maximum Total Area Occupied by Pistons

LeetCode 1959 - Minimum Total Space Wasted With K Resizing Operations

LeetCode 1895 - Largest Magic Square

LeetCode 2483 - Minimum Penalty for a Shop

LeetCode 2615 - Sum of Distances

LeetCode 2536 - Increment Submatrices by One

LeetCode 1872 - Stone Game VIII

LeetCode 2478 - Number of Beautiful Partitions