Robina Li

You are given an integer array coins representing coins of different denominations and an integer amount representing a total amount of money.

Difficulty: Medium Category: Backtracking, Recursion, Duplicates

Given two integers n and k, return all possible combinations of k numbers chosen from the range [1, n].

Difficulty: Medium Category: Backtracking, Recursion

Difficulty: Medium Category: Tree, Binary Tree, LCA

Difficulty: Medium Category: Design, Data Structure

Difficulty: Medium Category: Tree, DFS, BFS, Graph

Difficulty: Hard Category: Stack, Monotonic Stack

Difficulty: Medium Category: DFS, Graph, Matrix

Difficulty: Medium Category: Run-Length Encoding, Two Pointers, Array Processing