LeetCode practice notes for problems 1000 through 1100, covering interval DP, sliding window, binary search, greedy, SQL, and more.
| # | Title | Difficulty | Description |
|---|---|---|---|
| 1000 | LeetCode 1000: Minimum Cost to Merge Stones | Hard | A clear explanation of merging consecutive stone piles with minimum cost using interval dynamic programming. |
| 1001 | LeetCode 1001: Grid Illumination | Hard | A clear explanation of simulating lamp illumination on a grid using hash maps for rows, columns, and diagonals. |
| 1002 | LeetCode 1002: Find Common Characters | Easy | A clear explanation of finding characters that appear in all words using minimum frequency counts. |
| 1003 | LeetCode 1003: Check If Word Is Valid After Substitutions | Medium | A clear explanation of validating a string by repeatedly removing ‘abc’ substrings using a stack. |
| 1004 | LeetCode 1004: Max Consecutive Ones III | Medium | A clear explanation of finding the longest subarray of ones by flipping at most k zeros using a sliding window. |
| 1005 | LeetCode 1005: Maximize Sum Of Array After K Negations | Easy | A clear explanation of maximizing array sum after exactly k negations using a greedy strategy. |
| 1006 | LeetCode 1006: Clumsy Factorial | Medium | A clear explanation of computing the clumsy factorial by simulating cyclic operators with a stack. |
| 1007 | LeetCode 1007: Minimum Domino Rotations For Equal Row | Medium | A clear explanation of finding minimum rotations to make all tops or bottoms equal using a greedy candidate check. |
| 1008 | LeetCode 1008: Construct Binary Search Tree from Preorder Traversal | Medium | A clear explanation of reconstructing a BST from its preorder traversal using value range bounds. |
| 1009 | LeetCode 1009: Complement of Base 10 Integer | Easy | A clear explanation of finding the complement of a number by XORing with a bitmask of the same bit length. |
| 1010 | LeetCode 1010: Pairs of Songs With Total Durations Divisible by 60 | Medium | A clear explanation of counting song pairs whose total duration is divisible by 60 using remainder frequency counting. |
| 1011 | LeetCode 1011: Capacity To Ship Packages Within D Days | Medium | A clear explanation of finding the minimum ship capacity to deliver all packages within D days using binary search. |
| 1012 | LeetCode 1012: Numbers With Repeated Digits | Hard | A clear explanation of counting numbers up to n with at least one repeated digit using digit DP and combinatorics. |
| 1013 | LeetCode 1013: Partition Array Into Three Parts With Equal Sum | Easy | A clear explanation of checking if an array can be split into three contiguous parts with equal sum using a greedy two-pass approach. |
| 1014 | LeetCode 1014: Best Sightseeing Pair | Medium | A clear explanation of maximizing the sightseeing score by tracking the best left value seen so far in a single pass. |
| 1015 | LeetCode 1015: Smallest Integer Divisible by K | Medium | A clear explanation of finding the smallest repunit divisible by K by tracking remainders to detect cycles. |
| 1016 | LeetCode 1016: Binary String With Substrings Representing 1 To N | Medium | A clear explanation of checking whether a binary string contains all binary representations of integers from 1 to n. |
| 1017 | LeetCode 1017: Convert to Base -2 | Medium | A clear explanation of converting a non-negative integer to its base negative-two representation. |
| 1018 | LeetCode 1018: Binary Prefix Divisible By 5 | Easy | A clear explanation of checking divisibility of binary prefixes by 5 using running remainder tracking. |
| 1019 | LeetCode 1019: Next Greater Node In Linked List | Medium | A clear explanation of finding the next greater value for each node in a linked list using a monotonic stack. |
| 1020 | LeetCode 1020: Number of Enclaves | Medium | A clear explanation of counting land cells unreachable from the grid border using BFS from boundary land cells. |
| 1021 | LeetCode 1021: Remove Outermost Parentheses | Easy | A clear explanation of removing outermost parentheses from each primitive decomposition by tracking nesting depth. |
| 1022 | LeetCode 1022: Sum of Root To Leaf Binary Numbers | Easy | A clear explanation of summing root-to-leaf binary numbers in a binary tree using DFS with accumulated values. |
| 1023 | LeetCode 1023: Camelcase Matching | Medium | A clear explanation of checking camelCase pattern matching by verifying uppercase consistency with a two-pointer approach. |
| 1024 | LeetCode 1024: Video Stitching | Medium | A clear explanation of finding the minimum number of video clips to cover a time range using a greedy interval covering approach. |
| 1025 | LeetCode 1025: Divisor Game | Easy | A clear explanation of why Alice wins the divisor game if and only if n is even, proven by mathematical induction. |
| 1026 | LeetCode 1026: Maximum Difference Between Node and Ancestor | Medium | A clear explanation of finding the maximum ancestor-node difference in a binary tree by tracking min and max along each root-to-leaf path. |
| 1027 | LeetCode 1027: Longest Arithmetic Subsequence | Medium | A clear explanation of finding the longest arithmetic subsequence in an array using dynamic programming with difference hash maps. |
| 1028 | LeetCode 1028: Recover a Tree From Preorder Traversal | Hard | A clear explanation of reconstructing a binary tree from a depth-encoded preorder traversal string using a stack. |
| 1029 | LeetCode 1029: Two City Scheduling | Medium | A clear explanation of minimizing total travel cost for two-city scheduling using a greedy refund approach after sending everyone to city A. |
| 1030 | LeetCode 1030: Matrix Cells in Distance Order | Easy | A clear explanation of sorting matrix cells by Chebyshev distance from a given center cell using BFS. |
| 1031 | LeetCode 1031: Maximum Sum of Two Non-Overlapping Subarrays | Medium | A clear explanation of finding two non-overlapping subarrays with maximum combined sum using prefix sums and running maximums. |
| 1032 | LeetCode 1032: Stream of Characters | Hard | A clear explanation of efficiently querying a stream of characters against a word list using an Aho-Corasick trie. |
| 1033 | LeetCode 1033: Moving Stones Until Consecutive | Easy | A clear explanation of finding the minimum and maximum moves to make three stones consecutive by analyzing gap cases. |
| 1034 | LeetCode 1034: Coloring A Border | Medium | A clear explanation of coloring the border of a connected component in a grid using BFS. |
| 1035 | LeetCode 1035: Uncrossed Lines | Medium | A clear explanation of maximizing uncrossed connecting lines between two arrays using longest common subsequence dynamic programming. |
| 1036 | LeetCode 1036: Escape a Large Maze | Hard | A clear explanation of determining if a source can reach a target in a very large grid with blocked cells using BFS with a cell count limit. |
| 1037 | LeetCode 1037: Valid Boomerang | Easy | A clear explanation of checking if three points form a boomerang (non-collinear) using the cross product. |
| 1038 | LeetCode 1038: Binary Search Tree to Greater Sum Tree | Medium | A clear explanation of converting a BST to a greater sum tree by accumulating values in reverse inorder traversal. |
| 1039 | LeetCode 1039: Minimum Score Triangulation of Polygon | Medium | A clear explanation of minimizing the total score of triangulating a polygon using interval dynamic programming. |
| 1040 | LeetCode 1040: Moving Stones Until Consecutive II | Medium | A clear explanation of finding minimum and maximum moves to make stones consecutive using a sliding window. |
| 1041 | LeetCode 1041: Robot Bounded In Circle | Medium | A clear explanation of determining if a robot stays in a bounded circle by checking position and direction after one instruction cycle. |
| 1042 | LeetCode 1042: Flower Planting With No Adjacent | Medium | A clear explanation of assigning 4 flower types to garden nodes with no adjacent conflicts using greedy graph coloring. |
| 1043 | LeetCode 1043: Partition Array for Maximum Sum | Medium | A clear explanation of maximizing array sum by partitioning into subarrays of at most k elements, each filled with their maximum value, using dynamic programming. |
| 1044 | LeetCode 1044: Longest Duplicate Substring | Hard | A clear explanation of finding the longest duplicate substring using binary search on length combined with Rabin-Karp rolling hash. |
| 1045 | LeetCode 1045: Customers Who Bought All Products | Medium | A clear explanation of finding customers who purchased every product in the catalog using GROUP BY and HAVING with COUNT DISTINCT. |
| 1046 | LeetCode 1046: Last Stone Weight | Easy | A clear explanation of simulating stone smashing to find the last remaining weight using a max heap. |
| 1047 | LeetCode 1047: Remove All Adjacent Duplicates In String | Easy | A clear explanation of eliminating adjacent duplicate character pairs from a string using a stack. |
| 1048 | LeetCode 1048: Longest String Chain | Medium | A clear explanation of finding the longest word chain where each word is formed by inserting one letter into the previous word, using dynamic programming. |
| 1049 | LeetCode 1049: Last Stone Weight II | Medium | A clear explanation of minimizing the last stone weight by splitting stones into two groups using 0/1 knapsack dynamic programming. |
| 1050 | LeetCode 1050: Actors and Directors Who Cooperated At Least Three Times | Easy | A clear explanation of finding actor-director pairs with at least three collaborations using GROUP BY and HAVING. |
| 1051 | LeetCode 1051: Height Checker | Easy | A clear explanation of counting students not in the expected height order by comparing the array to its sorted version. |
| 1052 | LeetCode 1052: Grumpy Bookstore Owner | Medium | A clear explanation of maximizing satisfied customers by choosing the best window for the owner to not be grumpy using a sliding window. |
| 1053 | LeetCode 1053: Previous Permutation With One Swap | Medium | A clear explanation of finding the lexicographically largest permutation smaller than the given array using at most one swap. |
| 1054 | LeetCode 1054: Distant Barcodes | Medium | A clear explanation of rearranging barcodes so no two adjacent barcodes are equal using a greedy max-heap approach. |
| 1055 | LeetCode 1055: Shortest Way to Form String | Medium | A clear explanation of finding the minimum number of subsequences of source needed to form target using greedy two-pointer scanning. |
| 1056 | LeetCode 1056: Confusing Number | Easy | A clear explanation of checking if a number becomes a different valid number when rotated 180 degrees. |
| 1057 | LeetCode 1057: Campus Bikes | Medium | A clear explanation of greedily assigning bikes to workers based on Manhattan distance, prioritizing by distance then worker then bike index. |
| 1058 | LeetCode 1058: Minimize Rounding Error to Meet Target | Medium | A clear explanation of minimizing total rounding error when rounding prices to meet a target sum using a greedy approach. |
| 1059 | LeetCode 1059: All Paths from Source Lead to Destination | Medium | A clear explanation of verifying that all paths from a source node lead to a destination using DFS with cycle detection. |
| 1060 | LeetCode 1060: Missing Element in Sorted Array | Medium | A clear explanation of finding the k-th missing number in a sorted array using binary search on the missing count. |
| 1061 | LeetCode 1061: Lexicographically Smallest Equivalent String | Medium | A clear explanation of finding the lexicographically smallest equivalent string using Union-Find with canonical representatives. |
| 1062 | LeetCode 1062: Longest Repeating Substring | Medium | A clear explanation of finding the longest substring that appears at least twice using binary search on length with rolling hash. |
| 1063 | LeetCode 1063: Number of Valid Subarrays | Hard | A clear explanation of counting subarrays where the leftmost element is not larger than any other element, using a monotonic stack. |
| 1064 | LeetCode 1064: Fixed Point | Easy | A clear explanation of finding the smallest index where arr[i] equals i using binary search on a sorted distinct array. |
| 1065 | LeetCode 1065: Index Pairs of a String | Easy | A clear explanation of finding all index pairs where a word from the list appears in a text string using a trie. |
| 1066 | LeetCode 1066: Campus Bikes II | Medium | A clear explanation of finding the minimum total Manhattan distance to assign bikes to workers using bitmask dynamic programming. |
| 1067 | LeetCode 1067: Digit Count in Range | Hard | A clear explanation of counting the occurrences of a specific digit in all numbers from 1 to n using digit dynamic programming. |
| 1068 | LeetCode 1068: Product Sales Analysis I | Easy | A clear explanation of retrieving product names and their sale years using a JOIN between Sales and Product tables. |
| 1069 | LeetCode 1069: Product Sales Analysis II | Easy | A clear explanation of computing total quantity sold per product using GROUP BY and SUM aggregation. |
| 1070 | LeetCode 1070: Product Sales Analysis III | Medium | A clear explanation of finding the first year each product was sold using a self-join or window function. |
| 1071 | LeetCode 1071: Greatest Common Divisor of Strings | Easy | A clear explanation of finding the longest string that divides both strings using the GCD of their lengths. |
| 1072 | LeetCode 1072: Flip Columns For Maximum Number of Equal Rows | Medium | A clear explanation of finding the maximum number of rows that can be made all-equal by flipping columns, using row pattern normalization. |
| 1073 | LeetCode 1073: Adding Negative Numbers | Easy | A clear explanation of adding two non-positive integers represented as arrays of digits. |
| 1074 | LeetCode 1074: Number of Submatrices That Sum to Target | Hard | A clear explanation of counting submatrices with a given sum using 2D prefix sums combined with the subarray sum equals k technique. |
| 1075 | LeetCode 1075: Project Employees I | Easy | A clear explanation of computing the average years of experience per project using JOIN and AVG aggregation. |
| 1076 | LeetCode 1076: Project Employees II | Easy | A clear explanation of finding the project with the most employees using GROUP BY, COUNT, and a subquery for the maximum. |
| 1077 | LeetCode 1077: Project Employees III | Medium | A clear explanation of finding the most experienced employee(s) for each project using a window function or correlated subquery. |
| 1078 | LeetCode 1078: Occurrences After Bigram | Easy | A clear explanation of finding all words that follow a two-word sequence in a text string. |
| 1079 | LeetCode 1079: Letter Tile Possibilities | Medium | A clear explanation of counting all distinct non-empty sequences from a set of letter tiles using backtracking with frequency counting. |
| 1080 | LeetCode 1080: Insufficient Nodes in Root to Leaf Paths | Medium | A clear explanation of pruning tree nodes where all root-to-leaf paths through them have sum less than a limit, using post-order DFS. |
| 1081 | LeetCode 1081: Smallest Subsequence of Distinct Characters | Medium | A clear explanation of finding the lexicographically smallest subsequence with all distinct characters using a greedy stack approach. |
| 1082 | LeetCode 1082: Sales Analysis I | Easy | A clear explanation of finding the best seller(s) by total price using GROUP BY, SUM, and a subquery for the maximum. |
| 1083 | LeetCode 1083: Sales Analysis II | Easy | A clear explanation of finding buyers who bought an iPhone but not an iPad using JOIN and NOT IN filtering. |
| 1084 | LeetCode 1084: Sales Analysis III | Easy | A clear explanation of finding products sold only in the first quarter of 2019 using GROUP BY with date range conditions. |
| 1085 | LeetCode 1085: Sum of Digits in the Minimum Number | Easy | A clear explanation of checking if the digit sum of the array minimum is odd or even. |
| 1086 | LeetCode 1086: High Five | Easy | A clear explanation of computing each student’s top-5 average score using sorting and grouping. |
| 1087 | LeetCode 1087: Brace Expansion | Medium | A clear explanation of generating all strings from a brace expansion pattern in lexicographic order using backtracking. |
| 1088 | LeetCode 1088: Confusing Number II | Hard | A clear explanation of counting confusing numbers up to n using digit backtracking with rotation validation. |
| 1089 | LeetCode 1089: Duplicate Zeros | Easy | A clear explanation of duplicating zeros in-place in an array without using extra space by working backwards. |
| 1090 | LeetCode 1090: Largest Values From Labels | Medium | A clear explanation of selecting the maximum sum subset under item and label count constraints using a greedy approach. |
| 1091 | LeetCode 1091: Shortest Path in Binary Matrix | Medium | A clear explanation of finding the shortest path from top-left to bottom-right in a binary matrix using BFS. |
| 1092 | LeetCode 1092: Shortest Common Supersequence | Hard | A clear explanation of finding the shortest string containing both input strings as subsequences using LCS dynamic programming. |
| 1093 | LeetCode 1093: Statistics from a Large Sample | Medium | A clear explanation of computing statistical measures (minimum, maximum, mean, median, mode) from a frequency count array. |
| 1094 | LeetCode 1094: Car Pooling | Medium | A clear explanation of determining if a car can transport all passengers using a difference array for passenger count tracking. |
| 1095 | LeetCode 1095: Find in Mountain Array | Hard | A clear explanation of finding a target in a mountain array using three binary searches on the interface API. |
| 1096 | LeetCode 1096: Brace Expansion II | Hard | A clear explanation of generating all strings from a brace expansion expression using recursive parsing and set union/concatenation. |
| 1097 | LeetCode 1097: Game Play Analysis V | Hard | A clear explanation of finding the fraction of players retained the day after their first login using self-join and window functions. |
| 1098 | LeetCode 1098: Unpopular Books | Medium | A clear explanation of finding books with fewer than 10 sales in the last year that were not sold in the last year using LEFT JOIN and GROUP BY. |
| 1099 | LeetCode 1099: Two Sum Less Than K | Easy | A clear explanation of finding the maximum sum of two numbers less than k using a two-pointer approach on a sorted array. |
| 1100 | LeetCode 1100: Find K-Length Substrings With No Repeated Characters | Medium | A clear explanation of counting substrings of length k with all unique characters using a sliding window. |
LeetCode 1000: Minimum Cost to Merge StonesA clear explanation of merging consecutive stone piles with minimum cost using interval dynamic programming.
LeetCode 1001: Grid IlluminationA clear explanation of simulating lamp illumination on a grid using hash maps for rows, columns, and diagonals.
LeetCode 1002: Find Common CharactersA clear explanation of finding characters that appear in all words using minimum frequency counts.
LeetCode 1003: Check If Word Is Valid After SubstitutionsA clear explanation of validating a string by repeatedly removing 'abc' substrings using a stack.
LeetCode 1004: Max Consecutive Ones IIIA clear explanation of finding the longest subarray of ones by flipping at most k zeros using a sliding window.
LeetCode 1005: Maximize Sum Of Array After K NegationsA clear explanation of maximizing array sum after exactly k negations using a greedy strategy.
LeetCode 1006: Clumsy FactorialA clear explanation of computing the clumsy factorial by simulating cyclic operators with a stack.
LeetCode 1007: Minimum Domino Rotations For Equal RowA clear explanation of finding minimum rotations to make all tops or bottoms equal using a greedy candidate check.
LeetCode 1008: Construct Binary Search Tree from Preorder TraversalA clear explanation of reconstructing a BST from its preorder traversal using value range bounds.
LeetCode 1009: Complement of Base 10 IntegerA clear explanation of finding the complement of a number by XORing with a bitmask of the same bit length.
LeetCode 1010: Pairs of Songs With Total Durations Divisible by 60A clear explanation of counting song pairs whose total duration is divisible by 60 using remainder frequency counting.
LeetCode 1011: Capacity To Ship Packages Within D DaysA clear explanation of finding the minimum ship capacity to deliver all packages within D days using binary search.
LeetCode 1012: Numbers With Repeated DigitsA clear explanation of counting numbers up to n with at least one repeated digit using digit DP and combinatorics.
LeetCode 1013: Partition Array Into Three Parts With Equal SumA clear explanation of checking if an array can be split into three contiguous parts with equal sum using a greedy two-pass approach.
LeetCode 1014: Best Sightseeing PairA clear explanation of maximizing the sightseeing score by tracking the best left value seen so far in a single pass.
LeetCode 1015: Smallest Integer Divisible by KA clear explanation of finding the smallest repunit divisible by K by tracking remainders to detect cycles.
LeetCode 1016: Binary String With Substrings Representing 1 To NA clear explanation of checking whether a binary string contains all binary representations of integers from 1 to n.
LeetCode 1017: Convert to Base -2A clear explanation of converting a non-negative integer to its base negative-two representation.
LeetCode 1018: Binary Prefix Divisible By 5A clear explanation of checking divisibility of binary prefixes by 5 using running remainder tracking.
LeetCode 1019: Next Greater Node In Linked ListA clear explanation of finding the next greater value for each node in a linked list using a monotonic stack.
LeetCode 1020: Number of EnclavesA clear explanation of counting land cells unreachable from the grid border using BFS from boundary land cells.
LeetCode 1021: Remove Outermost ParenthesesA clear explanation of removing outermost parentheses from each primitive decomposition by tracking nesting depth.
LeetCode 1022: Sum of Root To Leaf Binary NumbersA clear explanation of summing root-to-leaf binary numbers in a binary tree using DFS with accumulated values.
LeetCode 1023: Camelcase MatchingA clear explanation of checking camelCase pattern matching by verifying uppercase consistency with a two-pointer approach.
LeetCode 1024: Video StitchingA clear explanation of finding the minimum number of video clips to cover a time range using a greedy interval covering approach.
LeetCode 1025: Divisor GameA clear explanation of why Alice wins the divisor game if and only if n is even, proven by mathematical induction.
LeetCode 1026: Maximum Difference Between Node and AncestorA clear explanation of finding the maximum ancestor-node difference in a binary tree by tracking min and max along each root-to-leaf path.
LeetCode 1027: Longest Arithmetic SubsequenceA clear explanation of finding the longest arithmetic subsequence in an array using dynamic programming with difference hash maps.
LeetCode 1028: Recover a Tree From Preorder TraversalA clear explanation of reconstructing a binary tree from a depth-encoded preorder traversal string using a stack.
LeetCode 1029: Two City SchedulingA clear explanation of minimizing total travel cost for two-city scheduling using a greedy refund approach after sending everyone to city A.
LeetCode 1030: Matrix Cells in Distance OrderA clear explanation of sorting matrix cells by Chebyshev distance from a given center cell using BFS.
LeetCode 1031: Maximum Sum of Two Non-Overlapping SubarraysA clear explanation of finding two non-overlapping subarrays with maximum combined sum using prefix sums and running maximums.
LeetCode 1032: Stream of CharactersA clear explanation of efficiently querying a stream of characters against a word list using an Aho-Corasick trie.
LeetCode 1033: Moving Stones Until ConsecutiveA clear explanation of finding the minimum and maximum moves to make three stones consecutive by analyzing gap cases.
LeetCode 1034: Coloring A BorderA clear explanation of coloring the border of a connected component in a grid using BFS.
LeetCode 1035: Uncrossed LinesA clear explanation of maximizing uncrossed connecting lines between two arrays using longest common subsequence dynamic programming.
LeetCode 1036: Escape a Large MazeA clear explanation of determining if a source can reach a target in a very large grid with blocked cells using BFS with a cell count limit.
LeetCode 1037: Valid BoomerangA clear explanation of checking if three points form a boomerang (non-collinear) using the cross product.
LeetCode 1038: Binary Search Tree to Greater Sum TreeA clear explanation of converting a BST to a greater sum tree by accumulating values in reverse inorder traversal.
LeetCode 1039: Minimum Score Triangulation of PolygonA clear explanation of minimizing the total score of triangulating a polygon using interval dynamic programming.
LeetCode 1040: Moving Stones Until Consecutive IIA clear explanation of finding minimum and maximum moves to make stones consecutive using a sliding window.
LeetCode 1041: Robot Bounded In CircleA clear explanation of determining if a robot stays in a bounded circle by checking position and direction after one instruction cycle.
LeetCode 1042: Flower Planting With No AdjacentA clear explanation of assigning 4 flower types to garden nodes with no adjacent conflicts using greedy graph coloring.
LeetCode 1043: Partition Array for Maximum SumA clear explanation of maximizing array sum by partitioning into subarrays of at most k elements, each filled with their maximum value, using dynamic programming.
LeetCode 1044: Longest Duplicate SubstringA clear explanation of finding the longest duplicate substring using binary search on length combined with Rabin-Karp rolling hash.
LeetCode 1045: Customers Who Bought All ProductsA clear explanation of finding customers who purchased every product in the catalog using GROUP BY and HAVING with COUNT DISTINCT.
LeetCode 1046: Last Stone WeightA clear explanation of simulating stone smashing to find the last remaining weight using a max heap.
LeetCode 1047: Remove All Adjacent Duplicates In StringA clear explanation of eliminating adjacent duplicate character pairs from a string using a stack.
LeetCode 1048: Longest String ChainA clear explanation of finding the longest word chain where each word is formed by inserting one letter into the previous word, using dynamic programming.
LeetCode 1049: Last Stone Weight IIA clear explanation of minimizing the last stone weight by splitting stones into two groups using 0/1 knapsack dynamic programming.
LeetCode 1050: Actors and Directors Who Cooperated At Least Three TimesA clear explanation of finding actor-director pairs with at least three collaborations using GROUP BY and HAVING.
LeetCode 1051: Height CheckerA clear explanation of counting students not in the expected height order by comparing the array to its sorted version.
LeetCode 1052: Grumpy Bookstore OwnerA clear explanation of maximizing satisfied customers by choosing the best window for the owner to not be grumpy using a sliding window.
LeetCode 1053: Previous Permutation With One SwapA clear explanation of finding the lexicographically largest permutation smaller than the given array using at most one swap.
LeetCode 1054: Distant BarcodesA clear explanation of rearranging barcodes so no two adjacent barcodes are equal using a greedy max-heap approach.
LeetCode 1055: Shortest Way to Form StringA clear explanation of finding the minimum number of subsequences of source needed to form target using greedy two-pointer scanning.
LeetCode 1056: Confusing NumberA clear explanation of checking if a number becomes a different valid number when rotated 180 degrees.
LeetCode 1057: Campus BikesA clear explanation of greedily assigning bikes to workers based on Manhattan distance, prioritizing by distance then worker then bike index.
LeetCode 1058: Minimize Rounding Error to Meet TargetA clear explanation of minimizing total rounding error when rounding prices to meet a target sum using a greedy approach.
LeetCode 1059: All Paths from Source Lead to DestinationA clear explanation of verifying that all paths from a source node lead to a destination using DFS with cycle detection.
LeetCode 1060: Missing Element in Sorted ArrayA clear explanation of finding the k-th missing number in a sorted array using binary search on the missing count.
LeetCode 1061: Lexicographically Smallest Equivalent StringA clear explanation of finding the lexicographically smallest equivalent string using Union-Find with canonical representatives.
LeetCode 1062: Longest Repeating SubstringA clear explanation of finding the longest substring that appears at least twice using binary search on length with rolling hash.
LeetCode 1063: Number of Valid SubarraysA clear explanation of counting subarrays where the leftmost element is not larger than any other element, using a monotonic stack.
LeetCode 1064: Fixed PointA clear explanation of finding the smallest index where arr[i] equals i using binary search on a sorted distinct array.
LeetCode 1065: Index Pairs of a StringA clear explanation of finding all index pairs where a word from the list appears in a text string using a trie.
LeetCode 1066: Campus Bikes IIA clear explanation of finding the minimum total Manhattan distance to assign bikes to workers using bitmask dynamic programming.
LeetCode 1067: Digit Count in RangeA clear explanation of counting the occurrences of a specific digit in all numbers from 1 to n using digit dynamic programming.
LeetCode 1068: Product Sales Analysis IA clear explanation of retrieving product names and their sale years using a JOIN between Sales and Product tables.
LeetCode 1069: Product Sales Analysis IIA clear explanation of computing total quantity sold per product using GROUP BY and SUM aggregation.
LeetCode 1070: Product Sales Analysis IIIA clear explanation of finding the first year each product was sold using a self-join or window function.
LeetCode 1071: Greatest Common Divisor of StringsA clear explanation of finding the longest string that divides both strings using the GCD of their lengths.
LeetCode 1072: Flip Columns For Maximum Number of Equal RowsA clear explanation of finding the maximum number of rows that can be made all-equal by flipping columns, using row pattern normalization.
LeetCode 1073: Adding Negative NumbersA clear explanation of adding two non-positive integers represented as arrays of digits.
LeetCode 1074: Number of Submatrices That Sum to TargetA clear explanation of counting submatrices with a given sum using 2D prefix sums combined with the subarray sum equals k technique.
LeetCode 1075: Project Employees IA clear explanation of computing the average years of experience per project using JOIN and AVG aggregation.
LeetCode 1076: Project Employees IIA clear explanation of finding the project with the most employees using GROUP BY, COUNT, and a subquery for the maximum.
LeetCode 1077: Project Employees IIIA clear explanation of finding the most experienced employee(s) for each project using a window function or correlated subquery.
LeetCode 1078: Occurrences After BigramA clear explanation of finding all words that follow a two-word sequence in a text string.
LeetCode 1079: Letter Tile PossibilitiesA clear explanation of counting all distinct non-empty sequences from a set of letter tiles using backtracking with frequency counting.
LeetCode 1080: Insufficient Nodes in Root to Leaf PathsA clear explanation of pruning tree nodes where all root-to-leaf paths through them have sum less than a limit, using post-order DFS.
LeetCode 1081: Smallest Subsequence of Distinct CharactersA clear explanation of finding the lexicographically smallest subsequence with all distinct characters using a greedy stack approach.
LeetCode 1082: Sales Analysis IA clear explanation of finding the best seller(s) by total price using GROUP BY, SUM, and a subquery for the maximum.
LeetCode 1083: Sales Analysis IIA clear explanation of finding buyers who bought an iPhone but not an iPad using JOIN and NOT IN filtering.
LeetCode 1084: Sales Analysis IIIA clear explanation of finding products sold only in the first quarter of 2019 using GROUP BY with date range conditions.
LeetCode 1085: Sum of Digits in the Minimum NumberA clear explanation of checking if the digit sum of the array minimum is odd or even.
LeetCode 1086: High FiveA clear explanation of computing each student's top-5 average score using sorting and grouping.
LeetCode 1087: Brace ExpansionA clear explanation of generating all strings from a brace expansion pattern in lexicographic order using backtracking.
LeetCode 1088: Confusing Number IIA clear explanation of counting confusing numbers up to n using digit backtracking with rotation validation.
LeetCode 1089: Duplicate ZerosA clear explanation of duplicating zeros in-place in an array without using extra space by working backwards.
LeetCode 1090: Largest Values From LabelsA clear explanation of selecting the maximum sum subset under item and label count constraints using a greedy approach.
LeetCode 1091: Shortest Path in Binary MatrixA clear explanation of finding the shortest path from top-left to bottom-right in a binary matrix using BFS.
LeetCode 1092: Shortest Common SupersequenceA clear explanation of finding the shortest string containing both input strings as subsequences using LCS dynamic programming.
LeetCode 1093: Statistics from a Large SampleA clear explanation of computing statistical measures (minimum, maximum, mean, median, mode) from a frequency count array.
LeetCode 1094: Car PoolingA clear explanation of determining if a car can transport all passengers using a difference array for passenger count tracking.
LeetCode 1095: Find in Mountain ArrayA clear explanation of finding a target in a mountain array using three binary searches on the interface API.
LeetCode 1096: Brace Expansion IIA clear explanation of generating all strings from a brace expansion expression using recursive parsing and set union/concatenation.
LeetCode 1097: Game Play Analysis VA clear explanation of finding the fraction of players retained the day after their first login using self-join and window functions.
LeetCode 1098: Unpopular BooksA clear explanation of finding books with fewer than 10 sales in the last year that were not sold in the last year using LEFT JOIN and GROUP BY.
LeetCode 1099: Two Sum Less Than KA clear explanation of finding the maximum sum of two numbers less than k using a two-pointer approach on a sorted array.
LeetCode 1100: Find K-Length Substrings With No Repeated CharactersA clear explanation of counting substrings of length k with all unique characters using a sliding window.