Connect Ropes with Minimum Cost

Connect ropes with minimum cost using greedy approach with heap Read full solution .

Maximize Sum After K Negations

Maximize array sum by flipping signs of k elements using greedy heap approach Read full solution .

Find K Largest Elements

Find the k largest elements from an unsorted array Read full solution .

Find K Smallest Elements

Find the k smallest elements from an unsorted array Read full solution .

Furthest Building You Can Reach

Find furthest building reachable using optimal allocation of bricks and ladders Read full solution .

Kth Largest Element in Array

Find the kth largest element in an unsorted array Read full solution .

Kth Smallest Element in Sorted Matrix

Find kth smallest element in row and column sorted matrix using heap Read full solution .

Find minimum number of meeting rooms required using heap Read full solution .

Merge K Sorted Arrays

Merge k sorted arrays into one sorted array using heap Read full solution .

Reduce Array Size to Half

Find minimum removals to reduce array size by half using greedy heap approach Read full solution .

Reorganize string so no two adjacent characters are the same Read full solution .

Sort Characters by Frequency

Sort characters in string by frequency using heap or bucket sort Read full solution .

Schedule tasks with cooling period using greedy approach with heap Read full solution .

Top K Frequent Elements

Find the k most frequent elements in an array Read full solution .

Ugly Numbers (Heap-based)

Find the nth ugly number using heap-based approach Read full solution .

Find Median from Data Stream

Design data structure to find median from continuous stream of integers Read full solution .

Minimum Number of Refueling Stops

Find minimum refueling stops to reach target using greedy max-heap approach Read full solution .

Sliding Window Median

Find median in each sliding window using two heaps Read full solution .

Heaps

Master heap data structures and priority queue implementations.

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QUESTION	DIFFICULTY
Connect Ropes with Minimum Cost Connect ropes with minimum cost using greedy approach with heap	Easy
Maximize Sum After K Negations Maximize array sum by flipping signs of k elements using greedy heap approach	Easy
Find K Largest Elements Find the k largest elements from an unsorted array	Medium
Find K Smallest Elements Find the k smallest elements from an unsorted array	Medium
Furthest Building You Can Reach Find furthest building reachable using optimal allocation of bricks and ladders	Medium
Kth Largest Element in Array Find the kth largest element in an unsorted array	Medium
Kth Smallest Element in Sorted Matrix Find kth smallest element in row and column sorted matrix using heap	Medium
Meeting Rooms II Find minimum number of meeting rooms required using heap	Medium
Merge K Sorted Arrays Merge k sorted arrays into one sorted array using heap	Medium
Reduce Array Size to Half Find minimum removals to reduce array size by half using greedy heap approach	Medium
Reorganize String Reorganize string so no two adjacent characters are the same	Medium
Sort Characters by Frequency Sort characters in string by frequency using heap or bucket sort	Medium
Task Scheduler Schedule tasks with cooling period using greedy approach with heap	Medium
Top K Frequent Elements Find the k most frequent elements in an array	Medium
Ugly Numbers (Heap-based) Find the nth ugly number using heap-based approach	Medium
Find Median from Data Stream Design data structure to find median from continuous stream of integers	Hard
Minimum Number of Refueling Stops Find minimum refueling stops to reach target using greedy max-heap approach	Hard
Sliding Window Median Find median in each sliding window using two heaps	Hard

Overview

Heaps are specialized tree-based data structures that maintain a specific ordering property. This section covers heap operations and their applications in solving interview problems.

Key Concepts

Min heap and max heap
Heap operations (insert, extract, peek)
Heapify process
Priority queues
K-way merge
Top K problems

Heaps

Overview

Key Concepts

Common Problems

Easy

Medium

Hard

Practice Tips

Resources