LeetCode 1094: Car Pooling
A clear explanation of determining if a car can transport all passengers using a difference array for passenger count tracking.
Tag
Heap
41 notes
LeetCode 1054: Distant Barcodes
A clear explanation of rearranging barcodes so no two adjacent barcodes are equal using a greedy max-heap approach.
LeetCode 1046: Last Stone Weight
A clear explanation of simulating stone smashing to find the last remaining weight using a max heap.
LeetCode 692: Top K Frequent Words
Find the k most frequent words using frequency counting and custom sorting by count and lexicographical order.
LeetCode 373: Find K Pairs with Smallest Sums
A clear explanation of finding the k smallest pair sums from two sorted arrays using a min heap and best-first search.
LeetCode 218: The Skyline Problem
A clear explanation of computing the skyline formed by buildings using sweep line and a max-heap.
LeetCode 23: Merge k Sorted Lists
A detailed explanation of merging k sorted linked lists using a min heap.
LeetCode 973: K Closest Points to Origin
A clear explanation of returning the k closest points to the origin using squared distance and sorting.
LeetCode 882: Reachable Nodes In Subdivided Graph
A clear explanation of counting reachable original and subdivided nodes using Dijkstra's shortest path algorithm.
LeetCode 871: Minimum Number of Refueling Stops
A clear explanation of minimizing refueling stops using a greedy max heap over reachable stations.
LeetCode 857: Minimum Cost to Hire K Workers
A clear explanation of hiring exactly k workers with minimum total cost using wage-to-quality ratios, sorting, and a max heap.
LeetCode 786: K-th Smallest Prime Fraction
A clear explanation of finding the kth smallest fraction from a sorted array using a min-heap.
LeetCode 778: Swim in Rising Water
A clear explanation of finding the minimum time to reach the bottom-right cell using a priority queue and minimax path reasoning.
LeetCode 767: Reorganize String
A clear explanation of rearranging characters so no two adjacent characters are equal using a greedy max heap.
LeetCode 703: Kth Largest Element in a Stream
A clear explanation of maintaining the kth largest element in a stream using a fixed-size min heap.
LeetCode 743: Network Delay Time
Find the time needed for a signal to reach all nodes in a directed weighted graph using Dijkstra's algorithm.
LeetCode 632: Smallest Range Covering Elements from K Lists
A heap-based solution for finding the smallest range that contains at least one number from each sorted list.
LeetCode 630: Course Schedule III
A greedy heap solution for taking the maximum number of courses before their deadlines.
LeetCode 502: IPO
A clear explanation of maximizing capital by selecting at most k projects using sorting and a max heap.
LeetCode 499: The Maze III
A clear explanation of finding the shortest rolling-ball path to the hole using Dijkstra with lexicographic tie-breaking.
LeetCode 480: Sliding Window Median
A clear explanation of maintaining the median of each fixed-size window using two heaps and lazy deletion.
LeetCode 407: Trapping Rain Water II
A clear explanation of trapping rain water in a 2D elevation map using a min heap and boundary expansion.
LeetCode 358: Rearrange String k Distance Apart
A clear explanation of rearranging a string so equal characters are at least k positions apart using a heap and cooldown queue.
LeetCode 355: Design Twitter
A clear explanation of implementing a simplified Twitter using hash maps, sets, timestamps, and a heap.
LeetCode 347: Top K Frequent Elements
A clear explanation of Top K Frequent Elements using frequency counting and bucket sort.
LeetCode 313: Super Ugly Number
A clear explanation of Super Ugly Number using dynamic programming with one pointer per prime.
LeetCode 295: Find Median from Data Stream
A two-heap data structure for adding numbers from a stream and returning the current median in constant time.
LeetCode 253: Meeting Rooms II
A clear explanation of the Meeting Rooms II problem using a min heap to track active meeting end times.
LeetCode 215: Kth Largest Element in an Array
A clear explanation of finding the kth largest element using sorting, a min-heap, and Quickselect.
1.5 Heaps and Priority Queues
Binary, d-ary, Fibonacci, pairing, soft heaps, double-ended structures, tournament trees, and concurrent priority queue designs.
Replacement Selection Run Generation
External sorting technique that uses a heap to produce initial sorted runs longer than the available memory.
Min Heap K Sorted Sort
Sort a k-sorted array using a sliding min heap window of size k+1.
K Sorted Array Sort
Sort an array where every element is at most k positions away from its final sorted position.
Ternary Heapsort
Heapsort variant that uses a ternary heap with three children per node.
Bottom Up Heapsort
Heapsort variant that uses bottom up sift down to reduce comparisons during heapify.
Heapsort
Comparison sorting algorithm that builds a heap and repeatedly extracts the maximum.
Kth Largest in Stream
Maintain the k-th largest value while values arrive one at a time.
Kth Smallest Fraction
Select the k-th smallest fraction formed by pairs from a sorted array using heap or binary search.
Streaming Top K
Maintain the k largest elements while values arrive one at a time.
Top K by Heap
Find the k largest or k smallest elements by maintaining a bounded heap.
Heap Select
Select the k-th smallest or largest element by maintaining a heap of candidate values.