1 Minimum Operations to Reduce an Integer to 0 Dynamic Programming Greedy Bit Manipulation
Medium 100
0.6% 2 String Compression Two Pointers String
Medium 88
0.6% 3 Time Needed to Rearrange a Binary String String Dynamic Programming Simulation
Medium 81
0.5% 4 LFU Cache Hash Table Linked List Design Doubly-Linked List
Hard 80
0.5% 5 Closest Equal Element Queries Array Hash Table Binary Search
Medium 77
0.5% 6 Smallest Substring With Identical Characters I Array Binary Search Enumeration
Hard 73
0.2% 7 Smallest Substring With Identical Characters II String Binary Search
Hard 73
0.4% 8 Remove Adjacent Almost-Equal Characters String Dynamic Programming Greedy
Medium 71
0.5% 9 Subarray Product Less Than K Array Binary Search Sliding Window Prefix Sum
Medium 70
0.5% 10 LRU Cache Hash Table Linked List Design Doubly-Linked List
Medium 67
0.5% 11 Maximum Number of Occurrences of a Substring Hash Table String Sliding Window
Medium 67
0.5% 12 Maximum Palindromes After Operations Array Hash Table String Greedy Sorting Counting
Medium 67
0.5% 13 Maximum Product of Three Numbers Array Math Sorting
Easy 66
0.5% 14 Minimize Malware Spread Array Hash Table Depth-First Search Breadth-First Search Union-Find Graph Theory
Hard 66
0.4% 15 Distinct Subsequences String Dynamic Programming
Hard 64
0.5% 16 Power Grid Maintenance Array Hash Table Depth-First Search Breadth-First Search Union-Find Graph Theory Heap (Priority Queue) Ordered Set
Medium 64
0.6% 17 Longest Substring Without Repeating Characters Hash Table String Sliding Window
Medium 62
0.4% 18 Count the Number of Fair Pairs Array Two Pointers Binary Search Sorting
Medium 62
0.5% 19 Maximum Frequency Stack Hash Table Stack Design Ordered Set
Hard 62
0.7% 20 Minimize Maximum Component Cost Binary Search Union-Find Graph Theory Sorting
Medium 62
0.4% 21 Group Anagrams Array Hash Table String Sorting
Medium 61
0.7% 22 Merge Intervals Array Sorting
Medium 61
0.5% 23 Check Whether Two Strings are Almost Equivalent Hash Table String Counting
Easy 61
0.6% 24 Number of Islands Array Depth-First Search Breadth-First Search Union-Find Matrix
Medium 61
0.6% 25 Course Schedule II Depth-First Search Breadth-First Search Graph Theory Topological Sort
Medium 61
0.6% 26 Beautiful Towers II Array Stack Monotonic Stack
Medium 61
0.4% 27 Beautiful Towers I Array Stack Monotonic Stack
Medium 61
0.4% 28 Check If a Number Is Majority Element in a Sorted Array Array Binary Search
Easy 61
0.6% 29 Height Checker Array Sorting Counting Sort
Easy 61
0.8% 30 Matrix Similarity After Cyclic Shifts Array Math Matrix Simulation
Easy 61
0.7% 31 Number of Self-Divisible Permutations Array Math Dynamic Programming Backtracking Bit Manipulation Number Theory Bitmask
Medium 61
0.7% 32 Maximum Number That Makes Result of Bitwise AND Zero String Greedy Sorting
Medium 61
0.7% 33 Find Subarray With Bitwise OR Closest to K Array Binary Search Bit Manipulation Segment Tree
Hard 61
0.3% 34 Equalize Strings by Adding or Removing Characters at Ends String Binary Search Dynamic Programming Sliding Window Hash Function
Medium 61
0.6% 35 Count the Number of Inversions Array Dynamic Programming
Hard 61
0.3% 36 Find the Minimum Area to Cover All Ones II Array Matrix Enumeration
Hard 61
0.6% 37 Find the Minimum Area to Cover All Ones I Array Matrix
Medium 61
0.8% 38 Maximum Height of a Triangle Array Enumeration
Easy 61
0.4% 39 Maximize Grid Happiness Dynamic Programming Bit Manipulation Memoization Bitmask
Hard 61
0.4% 40 Average Waiting Time Array Simulation
Medium 61
0.7% 41 Split a String in Balanced Strings String Greedy Counting
Easy 61
0.9% 42 Minimum Time to Visit All Houses Array Prefix Sum
Medium 61
0.7% 43 Palindromic Substrings Two Pointers String Dynamic Programming
Medium 58
0.7% 44 Delete and Earn Array Hash Table Dynamic Programming
Medium 58
0.6% 45 Binary Tree Maximum Path Sum Dynamic Programming Tree Depth-First Search Binary Tree
Hard 56
0.4% 46 Find the Last Marked Nodes in Tree Tree Depth-First Search
Hard 56
0.6% 47 Longest Common Subsequence String Dynamic Programming
Medium 56
0.6% 48 Best Time to Buy and Sell Stock Array Dynamic Programming
Easy 53
0.6% 49 Minimum Number of Taps to Open to Water a Garden Array Dynamic Programming Greedy
Hard 53
0.5% 50 Number of Divisible Triplet Sums Array Hash Table
Medium 53
0.7% 51 K-diff Pairs in an Array Array Hash Table Two Pointers Binary Search Sorting
Medium 53
0.5% 52 Reverse Nodes in k-Group Linked List Recursion
Hard 53
0.7% 53 All Nodes Distance K in Binary Tree Hash Table Tree Depth-First Search Breadth-First Search Binary Tree
Medium 53
0.7% 54 Count Subarrays With Median K Array Hash Table Prefix Sum
Hard 53
0.5% 55 Minimum Removals to Balance Array Array Binary Search Sliding Window Sorting
Medium 53
0.5% 56 Longest Palindromic Substring Two Pointers String Dynamic Programming
Medium 50
0.4% 57 Trapping Rain Water Array Two Pointers Dynamic Programming Stack Monotonic Stack
Hard 50
0.7% 58 Min Stack Stack Design
Medium 50
0.6% 59 Count Palindromic Subsequences String Dynamic Programming
Hard 50
0.4% 60 Number of Digit One Math Dynamic Programming Recursion
Hard 50
0.4% 61 Two Sum Array Hash Table
Easy 50
0.6% 62 Zigzag Conversion String
Medium 50
0.5% 63 Report Spam Message Array Hash Table String
Medium 50
0.5% 64 Minimum Window Substring Hash Table String Sliding Window
Hard 46
0.5% 65 Kth Largest Element in an Array Array Divide and Conquer Sorting Heap (Priority Queue) Quickselect
Medium 46
0.7% 66 Top K Frequent Elements Array Hash Table Divide and Conquer Sorting Heap (Priority Queue) Bucket Sort Counting Quickselect
Medium 46
0.7% 67 Asteroid Collision Array Stack Simulation
Medium 46
0.5% 68 Search Suggestions System Array String Binary Search Trie Sorting Heap (Priority Queue)
Medium 46
0.7% 69 Sum of Nodes with Even-Valued Grandparent Tree Depth-First Search Breadth-First Search Binary Tree
Medium 46
0.9% 70 Divide Array Into Arrays With Max Difference Array Greedy Sorting
Medium 46
0.8% 71 Maximum Units on a Truck Array Greedy Sorting
Easy 46
0.7% 72 Word Search Array String Backtracking Depth-First Search Matrix
Medium 46
0.5% 73 Koko Eating Bananas Array Binary Search
Medium 46
0.5% 74 Container With Most Water Array Two Pointers Greedy
Medium 42
0.6% 75 Merge k Sorted Lists Linked List Divide and Conquer Heap (Priority Queue) Merge Sort
Hard 42
0.6% 76 Sort Colors Array Two Pointers Sorting
Medium 42
0.7% 77 Validate Binary Search Tree Tree Depth-First Search Binary Search Tree Binary Tree
Medium 42
0.4% 78 Meeting Rooms II Array Two Pointers Greedy Sorting Heap (Priority Queue) Prefix Sum
Medium 42
0.5% 79 Coin Change Array Dynamic Programming Breadth-First Search
Medium 42
0.5% 80 Rotting Oranges Array Breadth-First Search Matrix
Medium 42
0.6% 81 Word Ladder Hash Table String Breadth-First Search
Hard 42
0.5% 82 Magnetic Force Between Two Balls Array Binary Search Sorting
Medium 42
0.7% 83 Largest Number After Digit Swaps by Parity Sorting Heap (Priority Queue)
Easy 42
0.7% 84 Maximum Subarray Array Divide and Conquer Dynamic Programming
Medium 42
0.5% 85 Minimum Absolute Difference Array Sorting
Easy 42
0.8% 86 Gas Station Array Greedy
Medium 42
0.5% 87 Median of Two Sorted Arrays Array Binary Search Divide and Conquer
Hard 42
0.5% 88 Minimum Difficulty of a Job Schedule Array Dynamic Programming
Hard 42
0.6% 89 Boundary of Binary Tree Tree Depth-First Search Binary Tree
Medium 42
0.5% 90 Odd String Difference Array Hash Table String
Easy 42
0.6% 91 Subarrays with K Different Integers Array Hash Table Sliding Window Counting
Hard 42
0.7% 92 Remove All Adjacent Duplicates in String II String Stack
Medium 42
0.6% 93 Path with Maximum Gold Array Backtracking Matrix
Medium 42
0.7% 94 3Sum Array Two Pointers Sorting
Medium 36
0.4% 95 Valid Parentheses String Stack
Easy 36
0.4% 96 Search in Rotated Sorted Array Array Binary Search
Medium 36
0.5% 97 First Missing Positive Array Hash Table
Hard 36
0.4% 98 Word Break Array Hash Table String Dynamic Programming Trie Memoization
Medium 36
0.5% 99 Maximal Square Array Dynamic Programming Matrix
Medium 36
0.5% 100 Find Median from Data Stream Two Pointers Design Sorting Heap (Priority Queue) Data Stream
Hard 36
0.5% 101 Decode String String Stack Recursion
Medium 36
0.6% 102 Count Binary Substrings Two Pointers String
Easy 36
0.7% 103 Top K Frequent Words Array Hash Table String Trie Sorting Heap (Priority Queue) Bucket Sort Counting
Medium 36
0.6% 104 Verify Preorder Sequence in Binary Search Tree Array Stack Tree Binary Search Tree Recursion Monotonic Stack Binary Tree
Medium 36
0.5% 105 Longest Increasing Path in a Matrix Array Dynamic Programming Depth-First Search Breadth-First Search Graph Theory Topological Sort Memoization Matrix
Hard 36
0.6% 106 Find Leaves of Binary Tree Tree Depth-First Search Binary Tree
Medium 36
0.8% 107 Longest Increasing Subsequence Array Binary Search Dynamic Programming
Medium 36
0.6% 108 Sliding Window Maximum Array Queue Sliding Window Heap (Priority Queue) Monotonic Queue
Hard 36
0.5% 109 Reorganize String Hash Table String Greedy Sorting Heap (Priority Queue) Counting
Medium 36
0.6% 110 Number of Visible People in a Queue Array Stack Monotonic Stack
Hard 36
0.7% 111 Max Consecutive Ones III Array Binary Search Sliding Window Prefix Sum
Medium 36
0.7% 112 Optimal Account Balancing Array Dynamic Programming Backtracking Bit Manipulation Bitmask
Hard 36
0.5% 113 Merge Two Sorted Lists Linked List Recursion
Easy 36
0.7% 114 All Possible Full Binary Trees Dynamic Programming Tree Recursion Memoization Binary Tree
Medium 36
0.8% 115 Maximal Rectangle Array Dynamic Programming Stack Matrix Monotonic Stack
Hard 36
0.6% 116 House Robber III Dynamic Programming Tree Depth-First Search Binary Tree
Medium 36
0.6% 117 Network Delay Time Depth-First Search Breadth-First Search Graph Theory Heap (Priority Queue) Shortest Path
Medium 36
0.6% 118 Reconstruct Itinerary Array String Depth-First Search Graph Theory Sorting Heap (Priority Queue) Eulerian Circuit
Hard 36
0.4% 119 Missing Number Array Hash Table Math Binary Search Bit Manipulation Sorting
Easy 36
0.7% 120 Design Twitter Hash Table Linked List Design Heap (Priority Queue)
Medium 36
0.4% 121 Diameter of N-Ary Tree Tree Depth-First Search
Medium 36
0.8% 122 Longest Continuous Subarray With Absolute Diff Less Than or Equal to Limit Array Queue Sliding Window Heap (Priority Queue) Ordered Set Monotonic Queue
Medium 36
0.6% 123 Valid Parenthesis String String Dynamic Programming Stack Greedy
Medium 36
0.4% 124 Course Schedule Depth-First Search Breadth-First Search Graph Theory Topological Sort
Medium 36
0.5% 125 Collect Coins in a Tree Array Tree Graph Theory Topological Sort
Hard 36
0.4% 126 Generate Parentheses String Dynamic Programming Backtracking
Medium 36
0.8% 127 Strange Printer String Dynamic Programming
Hard 36
0.6% 128 Maximum Team Size with Overlapping Intervals Medium 36
0.5% 129 Integer to Roman Hash Table Math String
Medium 28
0.7% 130 Roman to Integer Hash Table Math String
Easy 28
0.7% 131 Combination Sum Array Backtracking
Medium 28
0.8% 132 Product of Array Except Self Array Prefix Sum
Medium 28
0.7% 133 Masking Personal Information String
Medium 28
0.6% 134 Maximum Product Subarray Array Dynamic Programming
Medium 28
0.4% 135 Maximum Number of Ways to Partition an Array Array Hash Table Counting Enumeration Prefix Sum
Hard 28
0.4% 136 Maximum Number of Non-overlapping Palindrome Substrings Two Pointers String Dynamic Programming Greedy
Hard 28
0.4% 137 Basic Calculator Math String Stack Recursion
Hard 28
0.5% 138 K Closest Points to Origin Array Math Divide and Conquer Geometry Sorting Heap (Priority Queue) Quickselect
Medium 28
0.7% 139 Exclusive Time of Functions Array Stack
Medium 28
0.7% 140 Shortest Distance to Target String in a Circular Array Array String
Easy 28
0.7% 141 Game of Life Array Matrix Simulation
Medium 28
0.7% 142 Last Stone Weight Array Heap (Priority Queue)
Easy 28
0.7% 143 Path Sum III Tree Depth-First Search Binary Tree
Medium 28
0.5% 144 Candy Array Greedy
Hard 28
0.5% 145 Maximum Earnings From Taxi Array Hash Table Binary Search Dynamic Programming Sorting
Medium 28
0.5% 146 Least Number of Unique Integers after K Removals Array Hash Table Greedy Sorting Counting
Medium 28
0.6% 147 Backspace String Compare Two Pointers String Stack Simulation
Easy 28
0.5% 148 Design Snake Game Array Hash Table Design Queue Simulation
Medium 28
0.4% 149 Find Pivot Index Array Prefix Sum
Easy 28
0.6% 150 Encode and Decode TinyURL Hash Table String Design Hash Function
Medium 28
0.9% 151 Valid Palindrome Two Pointers String
Easy 28
0.5% 152 Max Chunks To Make Sorted II Array Stack Greedy Sorting Monotonic Stack
Hard 28
0.5% 153 Bus Routes Array Hash Table Breadth-First Search
Hard 28
0.5% 154 Minimum Equal Sum of Two Arrays After Replacing Zeros Array Greedy
Medium 28
0.5% 155 Finding the Number of Visible Mountains Array Stack Sorting Monotonic Stack
Medium 28
0.4% 156 Number of Operations to Make Network Connected Depth-First Search Breadth-First Search Union-Find Graph Theory
Medium 28
0.7% 157 Kth Largest Element in a Stream Tree Design Binary Search Tree Heap (Priority Queue) Binary Tree Data Stream
Easy 28
0.6% 158 Find Duplicate Subtrees Hash Table Tree Depth-First Search Binary Tree
Medium 28
0.6% 159 Course Schedule III Array Greedy Sorting Heap (Priority Queue)
Hard 28
0.4% 160 House Robber II Array Dynamic Programming
Medium 28
0.5% 161 Maximum Path Quality of a Graph Array Backtracking Graph Theory
Hard 28
0.6% 162 Partition Equal Subset Sum Array Dynamic Programming
Medium 28
0.5% 163 Tree Diameter Tree Depth-First Search Breadth-First Search Graph Theory Topological Sort
Medium 28
0.6% 164 Using a Robot to Print the Lexicographically Smallest String Hash Table String Stack Greedy
Medium 28
0.6% 165 Lexicographically Minimum String After Removing Stars Hash Table String Stack Greedy Heap (Priority Queue)
Medium 28
0.5% 166 Shortest Bridge Array Depth-First Search Breadth-First Search Matrix
Medium 28
0.6% 167 Count Vowel Substrings of a String Hash Table String
Easy 28
0.7% 168 Spiral Matrix Array Matrix Simulation
Medium 28
0.6% 169 Longest Substring Of All Vowels in Order String Sliding Window
Medium 28
0.5% 170 Find the Duplicate Number Array Two Pointers Binary Search Bit Manipulation
Medium 28
0.6% 171 Minimum Array Sum Array Dynamic Programming
Medium 28
0.3% 172 Construct Binary Tree from Preorder and Inorder Traversal Array Hash Table Divide and Conquer Tree Binary Tree
Medium 28
0.7% 173 Burst Balloons Array Dynamic Programming
Hard 28
0.6% 174 Time Taken to Cross the Door Array Queue Simulation
Hard 28
0.5% 175 Find K Closest Elements Array Two Pointers Binary Search Sliding Window Sorting Heap (Priority Queue)
Medium 28
0.5% 176 Coin Change II Array Dynamic Programming
Medium 28
0.6% 177 Sort Characters By Frequency Hash Table String Sorting Heap (Priority Queue) Bucket Sort Counting
Medium 28
0.8% 178 Time Based Key-Value Store Hash Table String Binary Search Design
Medium 28
0.5% 179 Vertical Order Traversal of a Binary Tree Hash Table Tree Depth-First Search Breadth-First Search Sorting Binary Tree
Hard 28
0.5% 180 Minimum Window Subsequence String Dynamic Programming Sliding Window
Hard 28
0.4% 181 Sliding Window Median Array Hash Table Sliding Window Heap (Priority Queue)
Hard 28
0.4% 182 Range Sum Query 2D - Immutable Array Design Matrix Prefix Sum
Medium 28
0.6% 183 Remove Stones to Minimize the Total Array Greedy Heap (Priority Queue)
Medium 28
0.7% 184 Minimum Replacements to Sort the Array Array Math Greedy
Hard 28
0.5% 185 Partition Array Into Two Arrays to Minimize Sum Difference Array Two Pointers Binary Search Dynamic Programming Bit Manipulation Sorting Ordered Set Bitmask
Hard 28
0.2% 186 Minimum Edge Reversals So Every Node Is Reachable Dynamic Programming Depth-First Search Breadth-First Search Graph Theory
Hard 28
0.6% 187 Subarray Sum Equals K Array Hash Table Prefix Sum
Medium 28
0.5% 188 Largest Rectangle in Histogram Array Stack Monotonic Stack
Hard 28
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