1 Design Authentication Manager Hash Table Linked List Design Doubly-Linked List
Medium 100
0.6% 2 Count Non Decreasing Arrays With Given Digit Sums Array Dynamic Programming Prefix Sum
Hard 100
0.4% 3 Implement Trie (Prefix Tree) Hash Table String Design Trie
Medium 88
0.7% 4 Find Maximum Area of a Triangle Array Hash Table Math Greedy Geometry Enumeration
Medium 88
0.3% 5 Longest Substring Without Repeating Characters Hash Table String Sliding Window
Medium 82
0.4% 6 Merge Intervals Array Sorting
Medium 82
0.5% 7 LRU Cache Hash Table Linked List Design Doubly-Linked List
Medium 82
0.5% 8 Insert Delete GetRandom O(1) Array Hash Table Math Design Randomized
Medium 82
0.6% 9 Search Suggestions System Array String Binary Search Trie Sorting Heap (Priority Queue)
Medium 82
0.7% 10 Top K Frequent Elements Array Hash Table Divide and Conquer Sorting Heap (Priority Queue) Bucket Sort Counting Quickselect
Medium 74
0.7% 11 Find Median from Data Stream Two Pointers Design Sorting Heap (Priority Queue) Data Stream
Hard 74
0.5% 12 Inorder Successor in BST Tree Depth-First Search Binary Search Tree Binary Tree
Medium 74
0.5% 13 Integer to Roman Hash Table Math String
Medium 74
0.7% 14 Number of Islands Array Depth-First Search Breadth-First Search Union-Find Matrix
Medium 74
0.6% 15 Logger Rate Limiter Hash Table Design Data Stream
Easy 74
0.8% 16 Group Anagrams Array Hash Table String Sorting
Medium 74
0.7% 17 Copy List with Random Pointer Hash Table Linked List
Medium 63
0.6% 18 Excel Sheet Column Number Math String
Easy 63
0.7% 19 Shortest Bridge Array Depth-First Search Breadth-First Search Matrix
Medium 63
0.6% 20 Count Good Nodes in Binary Tree Tree Depth-First Search Breadth-First Search Binary Tree
Medium 63
0.7% 21 Number of Atoms Hash Table String Stack Sorting
Hard 63
0.7% 22 House Robber II Array Dynamic Programming
Medium 63
0.5% 23 Meeting Rooms II Array Two Pointers Greedy Sorting Heap (Priority Queue) Prefix Sum
Medium 63
0.5% 24 House Robber III Dynamic Programming Tree Depth-First Search Binary Tree
Medium 63
0.6% 25 Minimum Cost to Make at Least One Valid Path in a Grid Array Breadth-First Search Graph Theory Heap (Priority Queue) Matrix Shortest Path
Hard 63
0.7% 26 Longest Repeating Character Replacement Hash Table String Sliding Window
Medium 63
0.6% 27 Word Ladder Hash Table String Breadth-First Search
Hard 63
0.5% 28 Merge Two Sorted Lists Linked List Recursion
Easy 63
0.7% 29 Task Scheduler Array Hash Table Greedy Sorting Heap (Priority Queue) Counting
Medium 63
0.6% 30 Spiral Matrix IV Array Linked List Matrix Simulation
Medium 63
0.8% 31 Find All Possible Recipes from Given Supplies Array Hash Table String Graph Theory Topological Sort
Medium 63
0.6% 32 Binary Tree Level Order Traversal Tree Breadth-First Search Binary Tree
Medium 63
0.7% 33 Trapping Rain Water Array Two Pointers Dynamic Programming Stack Monotonic Stack
Hard 63
0.7% 34 Maximum Profit in Job Scheduling Array Binary Search Dynamic Programming Sorting
Hard 63
0.5% 35 Find Peak Element Array Binary Search
Medium 63
0.5% 36 Accounts Merge Array Hash Table String Depth-First Search Breadth-First Search Union-Find Sorting
Medium 63
0.6%