# Heap

DSA

Sort Characters By Frequency

Max-heap on character frequency. Time O(n + d log d), Space O(d) where d = distinct characters.

Medium·Sep 16, 2026

DSA

K Closest Points to Origin

Max-heap of size k — evict the farthest point on each insert. Time O(n log k), Space O(k).

Medium·Sep 16, 2026

DSA Binary Search LeetCode

DSA

Find Kth Rotation

Binary Search. Time O(logn), Space O(1).

Easy·Aug 8, 2026

DSA

Median of 2 sorted Arrays

Covers: Naive, Two Pointer. Optimal — Time O(n+m), Space O(1).

DSA Binary Search LeetCode 🏢 Google 🏢 Amazon 🏢 Microsoft 🏢 Meta 🏢 Apple

DSA

K-th element of two Arrays

Covers: Naive, Two Pointer. Optimal — Time O(n+m), Space O(1).

DSA Binary Search LeetCode

DSA

Kth Largest in unsorted Array

Covers: Naive, Use Min Heap. Optimal — Time O(nlogk), Space O(1).

DSA Binary Tree LeetCode

DSA

Kth Largest Element in a Stream

Brute Force -> Sorting + Set approach. Optimal — Time O(nlogn), Space O(k).

Easy·Aug 8, 2026

DSA Binary Tree LeetCode

DSA

Find Median in Data Stream

4 approaches incl. Naive, Two Heaps, 1. How Do We Maintain the Me…, and more. Optimal — Time O(logn), Space O(n).

DSA Binary Tree LeetCode

DSA

Kth Smallest Element in a BST

Covers: Brute Force, Better, Optimal. Optimal — Time O(n), Space O(1).

DSA Binary Search Tree BST

DSA

Design Twitter

Covers: LinkedList + Hashmap, 📌 `getNewsFeed(int userId)`.

DSA Design LeetCode

DSA

Network Delay Time

Graphs — single-source shortest path with Dijkstra. Time O(E log V), Space O(V + E).

DSA Graphs Dijkstra 🏢 Google

DSA

Find Median from Data Stream

Covers: Brute Force, Follow Ups. Optimal — Space O(1).

DSA

Top K Frequent Elements

Summmary approach. Optimal — Time O(n log k), Space O(n).

DSA

Merge K sorted arrays

Covers: Naive, Using Min heap. Optimal — Time O(nlogk), Space O(k).

DSA

Maximum Sum Combination

Covers: Naive, Better, So the intuition is:. Optimal — Time O(n log n + K log K), Space O(K).

DSA

Kth Largest Element in an Array

Covers: Sort (Naive), Max Heap, Min Heap of Size k (Optimal). Optimal — Time O(n log k), Space O(k).

DSA

MinHeap/MaxHeap Implementation

Heaps problem — solution with code and analysis.

DSA

Cheapest Flights Within K Stops

Graphs problem — solution with code and analysis.