1 Two Sum 2 Median of Two Sorted Arrays 3 Regular Expression Matching 4 Letter Combinations of a Phone Number 5 Valid Parentheses 6 Generate Parentheses 7 Merge k Sorted Lists 8 Remove Duplicates from Sorted Array 9 Next Permutation 10 Trapping Rain Water 11 Wildcard Matching 12 Pow(x, n) 13 Spiral Matrix 14 Merge Intervals 15 Insert Interval 16 Plus One 17 Maximal Rectangle 18 Same Tree 19 Pascal's Triangle 20 Word Ladder 21 Longest Consecutive Sequence 22 Clone Graph 23 Word Break 24 Word Break II 25 LRU Cache 26 Min Stack 27 Find Peak Element 28 Fraction to Recurring Decimal 29 Binary Search Tree Iterator 30 House Robber 31 Number of Islands 32 Isomorphic Strings 33 Implement Trie (Prefix Tree) 34 Word Search II 35 Shortest Palindrome 36 The Skyline Problem 37 Count Complete Tree Nodes 38 Basic Calculator 39 Summary Ranges 40 Kth Smallest Element in a BST 41 Power of Two 42 Product of Array Except Self 43 Sliding Window Maximum 44 Search a 2D Matrix II 45 Binary Tree Paths 46 H-Index 47 Perfect Squares 48 Expression Add Operators 49 Move Zeroes 50 Peeking Iterator 51 Game of Life 52 Find Median from Data Stream 53 Serialize and Deserialize Binary Tree 54 Bulls and Cows 55 Longest Increasing Subsequence 56 Best Time to Buy and Sell Stock with Cooldown 57 Minimum Height Trees 58 Burst Balloons 59 Super Ugly Number 60 Count of Smaller Numbers After Self 61 Remove Duplicate Letters 62 Maximum Product of Word Lengths 63 Create Maximum Number 64 Wiggle Sort II 65 Power of Three 66 Count of Range Sum 67 Longest Increasing Path in a Matrix 68 Patching Array 69 Verify Preorder Serialization of a Binary Tree 70 Reconstruct Itinerary 71 Palindrome Pairs 72 Flatten Nested List Iterator 73 Reverse Vowels of a String 74 Russian Doll Envelopes 75 Count Numbers with Unique Digits 76 Max Sum of Rectangle No Larger Than K 77 Find K Pairs with Smallest Sums 78 Guess Number Higher or Lower 79 Guess Number Higher or Lower II 80 Combination Sum IV 81 Kth Smallest Element in a Sorted Matrix 82 Insert Delete GetRandom O(1) 83 Linked List Random Node 84 First Unique Character in a String 85 Longest Absolute File Path 86 Find the Difference 87 Perfect Rectangle 88 UTF-8 Validation 89 Decode String 90 Integer Replacement 91 Evaluate Division 92 Nth Digit 93 Binary Watch 94 Remove K Digits 95 Queue Reconstruction by Height 96 Trapping Rain Water II 97 Longest Palindrome 98 Split Array Largest Sum 99 Add Strings 100 Pacific Atlantic Water Flow 101 Maximum XOR of Two Numbers in an Array 102 Number of Boomerangs 103 Find All Numbers Disappeared in an Array 104 Sort Characters By Frequency 105 Repeated Substring Pattern 106 LFU Cache 107 Island Perimeter 108 Ones and Zeroes 109 Heaters 110 Sliding Window Median 111 Magical String 112 License Key Formatting 113 Smallest Good Base 114 Max Consecutive Ones 115 Predict the Winner 116 Reverse Pairs 117 Target Sum 118 Diagonal Traverse 119 Find Mode in Binary Search Tree 120 Next Greater Element II 121 Relative Ranks 122 Freedom Trail 123 Longest Palindromic Subsequence 124 Detect Capital 125 Longest Uncommon Subsequence I 126 Longest Uncommon Subsequence II 127 Longest Word in Dictionary through Deleting 128 Beautiful Arrangement 129 Minimum Absolute Difference in BST 130 Encode and Decode TinyURL 131 Reverse String II 132 01 Matrix 133 Diameter of Binary Tree 134 Student Attendance Record I 135 Student Attendance Record II 136 Subarray Sum Equals K 137 Shortest Unsorted Continuous Subarray 138 Delete Operation for Two Strings 139 Erect the Fence 140 Smallest Range Covering Elements from K Lists 141 Shopping Offers 142 Maximum Average Subarray I 143 Find Duplicate Subtrees 144 Find K Closest Elements 145 Split Array into Consecutive Subsequences 146 Non-decreasing Array 147 Beautiful Arrangement II 148 Kth Smallest Number in Multiplication Table 149 Implement Magic Dictionary 150 Valid Parenthesis String 151 24 Game 152 Redundant Connection 153 Redundant Connection II 154 Repeated String Match 155 Longest Univalue Path 156 Maximum Sum of 3 Non-Overlapping Subarrays 157 Find K-th Smallest Pair Distance 158 Number of Atoms 159 My Calendar I 160 My Calendar II 161 My Calendar III 162 Daily Temperatures 163 Largest Number At Least Twice of Others 164 Shortest Completing Word 165 Open the Lock 166 Cracking the Safe 167 Pyramid Transition Matrix 168 Couples Holding Hands 169 Toeplitz Matrix 170 Number of Matching Subsequences 171 Minimum Swaps To Make Sequences Increasing 172 Backspace String Compare 173 Maximize Distance to Closest Person 174 All Possible Full Binary Trees 175 Fruit Into Baskets 176 Long Pressed Name 177 Unique Email Addresses 178 Knight Dialer 179 Minimum Area Rectangle 180 K Closest Points to Origin 181 Odd Even Jump 182 Shortest Way to Form String 183 Campus Bikes 184 Confusing Number II 185 Video Stitching 186 Stream of Characters 187 Maximum Level Sum of a Binary Tree 188 String Transforms Into Another String 189 Number of Submatrices That Sum to Target 190 Divide Chocolate 191 Delete Nodes And Return Forest 192 Compare Strings by Frequency of the Smallest Character 193 Tiling a Rectangle with the Fewest Squares 194 Count Number of Nice Subarrays