1 Merge k Sorted Lists Linked List Divide and Conquer Heap (Priority Queue) Merge Sort
Hard 100
0.6% 2 Two Sum Array Hash Table
Easy 96
0.6% 3 Change Null Values in a Table to the Previous Value Database
Medium 85
0.5% 4 Valid Parentheses String Stack
Easy 77
0.4% 5 Second Highest Salary Database
Medium 77
0.5% 6 Best Time to Buy and Sell Stock Array Dynamic Programming
Easy 74
0.6% 7 Longest Palindromic Substring Two Pointers String Dynamic Programming
Medium 74
0.4% 8 Longest Substring Without Repeating Characters Hash Table String Sliding Window
Medium 74
0.4% 9 Palindrome Number Math
Easy 65
0.6% 10 Longest Common Prefix Array String Trie
Easy 65
0.5% 11 Container With Most Water Array Two Pointers Greedy
Medium 65
0.6% 12 Managers with at Least 5 Direct Reports Database
Medium 58
0.5% 13 Minimum Time to Repair Cars Array Binary Search
Medium 58
0.6% 14 Merge Intervals Array Sorting
Medium 58
0.5% 15 Maximum Subarray Array Divide and Conquer Dynamic Programming
Medium 58
0.5% 16 First Unique Character in a String Hash Table String Queue Counting
Easy 58
0.7% 17 Nth Highest Salary Database
Medium 58
0.4% 18 Group Anagrams Array Hash Table String Sorting
Medium 58
0.7% 19 3Sum Array Two Pointers Sorting
Medium 58
0.4% 20 Remove Duplicates from Sorted Array Array Two Pointers
Easy 58
0.6% 21 Add Binary Math String Bit Manipulation Simulation
Easy 58
0.6% 22 Climbing Stairs Math Dynamic Programming Memoization
Easy 58
0.5% 23 Valid Palindrome Two Pointers String
Easy 58
0.5% 24 Edit Distance String Dynamic Programming
Medium 49
0.6% 25 Coin Change Array Dynamic Programming Breadth-First Search
Medium 49
0.5% 26 Rising Temperature Database
Easy 49
0.5% 27 Max Consecutive Ones Array
Easy 49
0.7% 28 Kth Largest Element in an Array Array Divide and Conquer Sorting Heap (Priority Queue) Quickselect
Medium 49
0.7% 29 Customers Who Never Order Database
Easy 49
0.7% 30 Roman to Integer Hash Table Math String
Easy 49
0.7% 31 Reverse Pairs Array Binary Search Divide and Conquer Binary Indexed Tree Segment Tree Merge Sort Ordered Set
Hard 49
0.3% 32 Longest Consecutive Sequence Array Hash Table Union-Find
Medium 49
0.5% 33 Remove K-Balanced Substrings String Stack Simulation
Medium 49
0.3% 34 Split Array Largest Sum Array Binary Search Dynamic Programming Greedy Prefix Sum
Hard 49
0.6% 35 Shortest Unsorted Continuous Subarray Array Two Pointers Stack Greedy Sorting Monotonic Stack
Medium 49
0.4% 36 Rotate Array Array Math Two Pointers
Medium 49
0.5% 37 Valid Anagram Hash Table String Sorting
Easy 49
0.7% 38 Remove K Digits String Stack Greedy Monotonic Stack
Medium 49
0.4% 39 Remove All Adjacent Duplicates In String String Stack
Easy 49
0.7% 40 Subarray Sum Equals K Array Hash Table Prefix Sum
Medium 49
0.5% 41 Next Permutation Array Two Pointers
Medium 49
0.5% 42 Reverse Vowels of a String Two Pointers String
Easy 49
0.6% 43 Super Ugly Number Array Math Dynamic Programming
Medium 49
0.5%