1 Construct String With Repeat Limit Hash Table String Greedy Heap (Priority Queue) Counting
Medium 100
0.7% 2 Find the Town Judge Array Hash Table Graph Theory
Easy 98
0.5% 3 Reverse Nodes in k-Group Linked List Recursion
Hard 92
0.7% 4 Restore IP Addresses String Backtracking
Medium 92
0.6% 5 Reorder List Linked List Two Pointers Stack Recursion
Medium 85
0.7% 6 Reverse Linked List II Linked List
Medium 80
0.5% 7 Remove Linked List Elements Linked List Recursion
Easy 80
0.5% 8 Course Schedule II Depth-First Search Breadth-First Search Graph Theory Topological Sort
Medium 80
0.6% 9 LRU Cache Hash Table Linked List Design Doubly-Linked List
Medium 74
0.5% 10 Contains Duplicate II Array Hash Table Sliding Window
Easy 74
0.5% 11 Missing Number Array Hash Table Math Binary Search Bit Manipulation Sorting
Easy 74
0.7% 12 Inorder Successor in BST II Tree Binary Search Tree Binary Tree
Medium 74
0.6% 13 Maximum Depth of Binary Tree Tree Depth-First Search Breadth-First Search Binary Tree
Easy 74
0.8% 14 Search in Rotated Sorted Array Array Binary Search
Medium 74
0.5% 15 Copy List with Random Pointer Hash Table Linked List
Medium 74
0.6% 16 Rotated Digits Math Dynamic Programming
Medium 67
0.6% 17 Maximum Units on a Truck Array Greedy Sorting
Easy 67
0.7% 18 Permutations Array Backtracking
Medium 67
0.8% 19 Simplify Path String Stack
Medium 67
0.5% 20 Remove Duplicates from Sorted List II Linked List Two Pointers
Medium 67
0.5% 21 Merge In Between Linked Lists Linked List
Medium 57
0.8% 22 Kth Largest Element in a Stream Tree Design Binary Search Tree Heap (Priority Queue) Binary Tree Data Stream
Easy 57
0.6% 23 Palindromic Substrings Two Pointers String Dynamic Programming
Medium 57
0.7% 24 Path Sum II Backtracking Tree Depth-First Search Binary Tree
Medium 57
0.6% 25 Word Search Array String Backtracking Depth-First Search Matrix
Medium 57
0.5% 26 Longest Palindromic Substring Two Pointers String Dynamic Programming
Medium 57
0.4% 27 Maximum Subarray Array Divide and Conquer Dynamic Programming
Medium 57
0.5% 28 Word Break Array Hash Table String Dynamic Programming Trie Memoization
Medium 57
0.5% 29 Remove All Occurrences of a Substring String Stack Simulation
Medium 57
0.8% 30 Top K Frequent Elements Array Hash Table Divide and Conquer Sorting Heap (Priority Queue) Bucket Sort Counting Quickselect
Medium 57
0.7% 31 Edit Distance String Dynamic Programming
Medium 57
0.6% 32 Valid Palindrome Two Pointers String
Easy 57
0.5% 33 Longest Substring Without Repeating Characters Hash Table String Sliding Window
Medium 57
0.4% 34 Swap Nodes in Pairs Linked List Recursion
Medium 57
0.7% 35 Decode String String Stack Recursion
Medium 57
0.6% 36 Count Negative Numbers in a Sorted Matrix Array Binary Search Matrix
Easy 57
0.8% 37 Moving Average from Data Stream Array Design Queue Data Stream
Easy 57
0.8% 38 Implement Queue using Stacks Stack Design Queue
Easy 57
0.7% 39 Merge Two Sorted Lists Linked List Recursion
Easy 57
0.7%