Problems

Medium Unique Paths in Grid Algorithm · Dynamic Programming · Math Medium Product of Array Except Self Algorithm · Array · Prefix Sum Medium Sort Colors (Dutch National Flag) Array · Sorting · Two Pointers Medium Search in Rotated Sorted Array Algorithm · Array · Binary Search Medium Add Two Numbers (Linked List) Linked List · Math · Recursion Medium Combination Sum Array · Backtracking · Recursion Medium Longest Substring Without Repeating Characters Hash Table · Sliding Window · String Medium Permutations of an Array Array · Backtracking · Recursion Medium Longest Palindromic Substring Dynamic Programming · String · Two Pointers Medium Subsets (Power Set) Array · Backtracking · Bit Manipulation Medium String to Integer (atoi) Algorithm · Math · String Medium Word Search in Grid Array · Backtracking · DFS Medium Container With Most Water Array · Greedy · Two Pointers Medium Validate Binary Search Tree Binary Tree · BST · Recursion Medium 3Sum: Find Unique Triplets That Sum to Zero Array · Sorting · Two Pointers Medium Binary Tree Level Order Traversal BFS · Binary Tree · Queue Medium Generate All Valid Parentheses Combinations Backtracking · Recursion · String Medium Course Schedule (Detect Cycle) DFS · Graph · Topological Sort Medium Group Anagrams Hash Table · Sorting · String Medium Number of Islands BFS · DFS · Graph Medium Pow(x, n): Fast Exponentiation Algorithm · Math · Recursion Medium House Robber: Maximize Loot Algorithm · Array · Dynamic Programming Medium Rotate Image (90 Degrees) Array · Math · Matrix Medium Coin Change: Fewest Coins for Amount Array · BFS · Dynamic Programming Medium Spiral Matrix Traversal Algorithm · Array · Matrix Medium Letter Combinations of a Phone Number Backtracking · Recursion · String Medium Jump Game: Can You Reach the End? Array · Dynamic Programming · Greedy Medium Find First and Last Position Algorithm · Array · Binary Search Medium Merge Overlapping Intervals Algorithm · Array · Sorting Medium Top K Frequent Elements Array · Hash Table · Heap