| No. | # | Title | Solution | Difficulty | Solved Date | Tag | Review Date | |
|---|---|---|---|---|---|---|---|---|
| 1 | 461 | Hamming Distance | Java | Easy | 2017.1.6 | Math, Bit manipulation | 2018.1.19 2018.6.19 | |
| 2 | 412 | Fizz Buzz | Python Java | Easy | 2017.1.7 | String | 2018.1.14 2018.6.19 | |
| 3 | 344 | Reverse String | Java | Easy | 2017.1.7 | Two Pointers, String | 2018.1.8 2018.6.19 | |
| 4 | 463 | Island Perimeter | Python | Easy | 2017.1.8 | Array | 2018.1.19 2018.6.19 2018.10.10 2018.10.27 2018.11.12 | |
| 5 | 448 | Find All Numbers Disappeared in an array | Java | Easy | 2017.1.8 | Array | 2018.1.10 2018.5.14 2018.6.20 | |
| 6 | 136 | Single Number | Python, Java | Easy | 2017.1.10 | Hash Table, Bit Manipulation | 2018.5.4 2018.6.19 2018.10.10 2018.10.19 2018.10.30 2019.2.24 | |
| 7 | 371 | Sum of Two Integers | Java | Easy | 2017.1.10 | Bit Manipulation | 2018.10.11 | |
| 8 | 389 | Find the difference | Java | Easy | 2017.1.11 | Hash Table, Bit Manipulation | 2018.5.18 | |
| 9 | 476 | Number Complement | Python | Easy | 2017.1.12 | |||
| 10 | 455 | Assign-cookies | Python | Easy | 2017.1.16 | |||
| 11 | 453 | Minimum Moves to Equal Array Elements | Java | Easy | 2017.1.18 | Math | 2018.1.11 | |
| 12 | 118 | Pascal's Triangle | Java | Easy | 2017.2.20 | Array | 2018.1.6 | |
| 13 | 21 | Merge Two Sorted Lists | Java | Easy | 2017.2.20 | Linked List | 2017.12.15 2018.1.5 2018.2.10 2018.4.12 2018.7.7 2018.10.12 2018.10.19 | |
| 14 | 1 | Two Sum | Java | Easy | 2017.3.9 | Array, Hash Table | 2017.12.13 2018.2.1 2018.2.25 2018.3.25 2018.3.28 2018.4.10 2018.4.16 2018.4.24 2018.5.29 2018.10.14 2019.2.17 | |
| 15 | 7 | Reverse Integer | Java | Easy | 2017.3.9 | Math | 2018.10.16 | |
| 16 | 9 | Palindrome Number | Java | Easy | 2017.3.9 | 2019.4.22 | ||
| 17 | 14 | Longest Common Prefix | Java | Easy | 2017.3.9 | String | 2017.12.24 2018.10.16 2018.10.26 | |
| 18 | 20 | Valid Parentheses | Java | Easy | 2017.3.9 | Stack | 2018.4.23 2018.10.27 2018.11.12 | |
| 19 | 26 | Remove Duplicates from Sorted Array | Java | Easy | 2017.3.10 | Array | 2018.2.11 2018.4.24 2018.6.22 2018.10.14 2018.10.15 | |
| 20 | 27 | Remove Element | Java | Easy | 2017.3.10 | |||
| 21 | 28 | Implement strStr() | Java | Easy | 2017.3.15 | String | 2018.3.17 | |
| 22 | 35 | Search Insert Position | Java | Easy | 2017.3.15 | |||
| 23 | 38 | Count and Say | Java | Easy | 2017.3.16 | String | 2018.10.15 | |
| 24 | 53 | Maximum Subarray | Java | Easy | 2017.3.16 | Array, Divide and Conquer,Dynamic Programming | 2017.12.17 2018.1.23 2018.1.27 2018.2.21 2018.4.17 2018.4.18 2018.5.24 2018.7.10 2018.9.14 2018.9.28 2018.10.14 2018.10.27 2018.11.8 | |
| 25 | 58 | Length of Last Word | Java | Easy | 2017.3.16 | |||
| 26 | 66 | Plus One | Java | Easy | 2017.3.17 | Math. Array | 2017.12.14 2018.10.14 | |
| 27 | 67 | Add Binary | Java | Easy | 2017.3.17 | Math, String | 2017.12.13 2018.10.15 2018.10.26 2018.11.10 | |
| 28 | 69 | Sqrt(x) | Java | Easy | 2017.3.17 | 2018.3.22 2018.11.7 | ||
| 29 | 88 | Merge Sorted Array | Java | Easy | 2017.3.21 | Array, Two Pointer | 2018.4.24 2018.10.16 2018.11.11 | |
| 30 | 101 | Symmetric Tree | Java | Easy | 2017.3.21 | Tree | 2018.1.1 2018.3.15 2018.4.19 2018.5.29 2018.7.9 2018.10.14 2019.3.3 | |
| 31 | 119 | Pascal's Triangle Ⅱ | Java | Easy | 2017.3.22 | |||
| 32 | 121 | Best Time to Buy and Sell Stock | Java | Easy | 2017.3.23 | Array, Dynamic Programming | 2017.12.17 2018.1.28 2018.2.21 2018.2.26 2018.4.13 2018.4.17 2018.5.24 2018.7.6 2018.10.12 2019.1.10 2019.2.12 | |
| 33 | 122 | Best Time to Buy and Sell Stock Ⅱ | Java | Easy | 2017.3.23 | Array, Greedy | 2017.12.18 2018.2.26 2018.10.11 2019.2.12 | |
| 34 | 167 | Two Sum Ⅱ - Input array is sorted | Java | Easy | 2017.3.24 | Array, Two Pointers, Binary Search | 2017.12.13 2018.4.10 2018.4.28 2019.2.17 | |
| 35 | 414 | Third Maximum Number | Java | Easy | 2017.3.27 | Array | 2017.11.3 2018.1.8 | |
| 36 | 268 | Missing Number | Java | Easy | 2017.3.27 | 2018.6.30 | ||
| 37 | 485 | Max Consecutive Ones | Java | Easy | 2017.3.28 | Array | 2018.10.27 2019.3.3 | |
| 38 | 219 | Contains Duplicate Ⅱ | Java | Easy | 2017.3.28 | Array, HashMap | 2018.2.14 2018.11.3 | |
| 39 | 500 | Keyboard Row | Java | Easy | 2017.4.1 | |||
| 40 | 349 | Intersection of Two Arrays | Java | Easy | 2017.4.1 | Array | 2018.10.11 2018.11.11 | |
| 41 | 409 | Longest Palindrome | Java | Easy | 2017.4.7 | HashTable | 2018.3.19 | |
| 42 | 350 | Intersection of Two Arrays Ⅱ | Java | Easy | 2017.4.7 | Two Pointers, HashMap | 2018.10.12 2018.11.11 | |
| 43 | 141 | Linked List Cycle | Java | Easy | 2017.5.25 | Linked List, Two Pointers | 2017.12.15 2018.1.24 2018.2.10 2018.4.10 2018.4.24 2018.10.15 2018.10.18 2019.2.10 | |
| 44 | 142 | Linked List Cycle Ⅱ | Java | Medium | 2017.5.25 | Linked List, Two Pointers | 2017.12.25 2018.2.10 2018.4.24 2018.10.18 | |
| 45 | 160 | Intersection of Two Linked Lists | Java | Easy | 2017.5.25 | Linked List | 2017.12.23 2018.1.9 2018.2.10 2018.4.10 2018.4.17 2018.10.16 | |
| 46 | 234 | Palindrome Linked List | Java | Easy | 2017.5.26 | Linked List, Two Pointers | 2017.12.23 2018.1.24 2018.2.11 2018.4.13 | |
| 47 | 203 | Remove Linked List Elements | Java | Easy | 2017.5.27 | Linked List | 2017.12.26 2018.2.11 | |
| 48 | 2 | Add Two Numbers | Java | Medium | 2017.5.27 | Linked List, Math | 2017.12.13 2018.1.26 2018.2.11 2018.4.17 2018.9.21 2018.10.21 | |
| 49 | 445 | Add Two Numbers Ⅱ | Java | Medium | 2017.5.30 | Linked List | 2017.12.13 2018.1.26 2018.2.12 2018.4.23 | |
| 50 | 24 | Swap Nodes in Pairs | Java | Medium | 2017.6.2 | Linked List | 2017.12.25 2018.9.27 | |
| 51 | 19 | Remove Nth Node From End of List | Java | Medium | 2017.6.2 | Linked List | 2017.12.25 2018.9.24 2018.10.18 | |
| 52 | 147 | Insertion Sort List | Java | Medium | 2017.6.7 | Linked List, Sort | ||
| 53 | 86 | Partition List | Java | Medium | 2017.6.7 | Linked List, Two Pointers | 2018.1.25 2018.10.3 | |
| 54 | 92 | Reverse Linked List Ⅱ | Java | Medium | 2017.6.8 | Linked List | 2018.2.12 | |
| 55 | 82 | Remove Duplicates from Sorted List Ⅱ | Java | Medium | 2017.6.8 | Linked List | 2018.10.2 | |
| 56 | 61 | Rotate List | Java | Medium | 2017.6.9 | Linked List, Two Pointers | 2018.2.12 2018.10.2 | |
| 57 | 25 | Reverse Nodes in k-Group | Java | Hard | 2017.6.10 | Linked List | 2018.11.17 | |
| 58 | 148 | Sort List | Java | Medium | 2017.6.11 | Linked List, Sort | 2017.12.15 2018.2.13 | |
| 59 | 237 | Delete Node in a Linked List | Java | Easy | 2017.6.14 | Linked List | 2017.12.14 2018.2.10 2018.6.30 | |
| 60 | 206 | Reverse Linked List | Java | Easy | 2017.6.14 | Linked List | 2017.12.15 2018.1.17 2018.2.8 2018.2.10 2018.3.11 2018.4.10 2018.6.30 2018.9.28 2018.10.11 | |
| 61 | 328 | Odd Even Linked List | Java | Medium | 2017.6.15 | Linked List | 2017.12.16 2018.2.11 | |
| 62 | 83 | Remove Duplicates from Sorted List | Java | Easy | 2017.6.15 | Linked List | 2017.12.26 | |
| 63 | 109 | Convert Sorted List to Binary Search Tree | Java | Medium | 2017.6.17 | Linked List, DFS | 2018.2.12 | |
| 64 | 496 | Next Greater Element I | Java | Easy | 2017.6.19 | Stack, HashMap | 2018.1.12 | |
| 65 | 503 | Next Greater Element II | Java | Medium | 2017.6.19 | Stack | 2018.1.13 | |
| 66 | 94 | Binary Tree Inorder Travelsal | Java | Medium | 2017.6.20 | Stack | 2018.1.4 2018.2.13 2018.3.15 2018.4.3 2018.4.24 2018.5.8 2018.6.8 2018.10.3 | |
| 67 | 144 | Binary Tree Preorder Travelsal | Java | Medium | 2017.6.22 | Stack | 2018.1.4 2018.2.13 2018.3.15 2018.4.24 2018.9.28 | |
| 68 | 145 | Binary Tree Postorder Travelsal | Java | Hard | 2017.6.22 | Stack | 2018.1.4 2018.2.13 2018.3.15 2018.4.24 2018.10.24 | |
| 69 | 394 | Decode String | Java | Medium | 2017.6.27 | Stack | 2018.1.9 | |
| 70 | 341 | Flatten Nested List Iterator | Java | Medium | 2017.6.27 | Design, Stack | 2018.1.8 2018.1.28 2018.10.26 | |
| 71 | 173 | Binary Search Tree Iterator | Java | Medium | 2017.6.27 | Stack | 2017.12.31 2018.1.7 2018.3.5 2018.4.18 2018.10.23 | |
| 72 | 155 | Min Stack | Java | Easy | 2017.7.4 | Stack | 2018.3.7 2018.4.11 | |
| 73 | 225 | Implement Stack using Queues | Java | Easy | 2017.7.5 | Stack | 2018.2.27 | |
| 74 | 232 | Implement Queue using Stacks | Java | Easy | 2017.7.5 | Queue | 2018.2.27 2018.4.23 2018.7.19 | |
| 75 | 331 | Verify Preorder Serialization of a Binary Tree | Java | Medium | 2017.7.6 | Stack | ||
| 76 | 561 | Array Partition I | Java | Easy | 2017.7.10 | Array | 2018.6.25 | |
| 77 | 189 | Rotate Array | Java | Easy | 2017.7.10 | Array | 2017.12.10 2018.4.10 2018.6.9 2018.10.27 | |
| 78 | 605 | Can Place Flowers | Java | Easy | 2017.7.10 | Array | ||
| 79 | 581 | Shortest Unsorted Continuous Subarray | Java | Easy | 2017.7.11 | Array | ||
| 80 | 566 | Reshape the Matrix | Java | Easy | 2017.7.11 | Array | ||
| 81 | 628 | Maximum Product of Three Numbers | Java | Easy | 2017.7.13 | Array | 2018.1.18 | |
| 82 | 105 | Construct Binary Tree from Preorder and Inorder Traversal | Java | Medium | 2017.7.14 | Array | 2017.7.16 2018.1.5 2018.2.13 2018.3.21 | |
| 83 | 106 | Construct Binary Tree from Inorder and Postorder Traversal | Java | Medium | 2017.7.15 | Array | 2017.7.16 2018.1.5 2018.2.13 2018.3.21 2018.10.14 2018.10.24 | |
| 84 | 532 | K-diff Pairs in an Array | Java | Easy | 2017.7.15 | Array | 2017.7.16 2018.1.8 2018.1.15 | |
| 85 | 521 | Longest Uncommon Subsequence I | Java | Easy | 2017.7.15 | String | 2017.7.16 | |
| 86 | 606 | Construct String from Binary Tree | Java | Easy | 2017.7.15 | String | ||
| 87 | 125 | Valid Palindrome | Java | Easy | 2017.7.15 | String | 2017.7.17 2018.1.6 2018.3.17 2018.4.24 2018.10.16 2018.10.27 2018.11.11 | |
| 88 | 520 | Detect Capital | Java | Easy | 2017.7.15 | String | 2017.7.17 2018.1.10 | |
| 89 | 383 | Ransom Note | Java | Easy | 2017.7.15 | String | 2018.9.4 | |
| 90 | 551 | Student Attendance Record I | Java | Easy | 2017.7.15 | String | ||
| 91 | 557 | Reverse Words in a String III | Java | Easy | 2017.7.18 | String | 2018.1.19 | |
| 92 | 541 | Reverse String II | Java | Easy | 2017.7.19 | String | 2018.1.8 | |
| 93 | 459 | Repeated Substring Pattern | Java | Easy | 2017.7.19 | String | 2018.1.15 | |
| 94 | 434 | Number of Segments in a String | Java | Easy | 2017.7.19 | String | 2018.1.16 | |
| 95 | 345 | Reverse Vowels of a String | Java | Easy | 2017.7.20 | String | 2018.1.16 | |
| 96 | 643 | Maximum Average Subarray I | Java | Easy | 2017.7.20 | Array | 2018.1.17 | |
| 97 | 594 | Longest Harmonious Subsequence | Java | Easy | 2017.7.20 | HashTable | 2018.1.20 | |
| 98 | 575 | Distribute Candies | Java | Easy | 2017.7.20 | HashTable | 2018.1.16 | |
| 99 | 447 | Number of Boomerangs | Java | Easy | 2017.7.20 | HashTable | 2018.1.20 | |
| 100 | 438 | Find All Anagrams in a String | Java | Easy | 2017.7.21 | HashMap | 2018.1.22 2018.10.10 2018.10.15 2018.10.27 2018.11.10 | |
| 101 | 599 | Minimum Index Sum of Two Lists | Java | Easy | 2017.7.21 | HashMap | 2018.1.17 | |
| 102 | 205 | Isomorphic Strings | Java | Easy | 2017.7.23 | Hash Table | 2018.1.7 2019.2.4 | |
| 103 | 645 | Set Mismatch | Java | Easy | 2017.7.23 | HashMap, Array | 2018.1.14 | |
| 104 | 204 | Count Primes | Java | Easy | 2017.7.24 | HashMap, Math | 2018.1.7 2018.3.18 | |
| 105 | 290 | Word Pattern | Java | Easy | 2017.7.24 | HashTable | 2018.1.7 2018.5.25 2019.2.20 | |
| 106 | 12 | Integer to Roman | Java | Medium | 2017.7.27 | Math, String | 2018.1.4 2018.3.7 2018.9.23 2018.10.28 | |
| 107 | 13 | Roman to Integer | Java | Easy | 2017.7.27 | Math, String | 2018.1.4 2018.3.7 2018.6.30 2018.10.11 2018.10.28 | |
| 108 | 111 | Minimum Depth of Binary Tree | Java | Easy | 2017.7.27 | Tree, DFS, BFS | 2018.1.4 2018.5.29 2018.10.15 | |
| 109 | 617 | Merge Two Binary Trees | Java | Easy | 2017.7.31 | Tree | 2017.12.30 2018.1.14 2018.2.5 2018.4.9 2018.6.8 | |
| 110 | 70 | Climbing Stairs | Java | Easy | 2017.8.2 | Dynamic Programming | 2017.12.17 2018.1.5 2018.2.21 2018.3.10 2018.4.17 2018.5.24 | |
| 111 | 100 | Same Tree | Java | Easy | 2017.8.4 | Tree, DFS | 2017.12.30 2018.1.5 2018.2.19 2018.4.3 | |
| 112 | 169 | Majority Element | Java | Easy | 2017.8.6 | Array, Divide and Conquer, Bit Manipulation | 2018.1.6 2018.2.6 2018.3.2 2018.7.19 | |
| 113 | 171 | Excel Sheet Column Number | Java | Easy | 2017.8.6 | Math | 2018.1.7 2018.6.30 2018.10.28 | |
| 114 | 690 | Employee Importance | Java | Easy | 2017.10.11 | DFS | 2018.5.28 | |
| 115 | 695 | Max Area of Island | Java | Easy | 2017.10.12 | DFS | 2018.1.18 | |
| 116 | 693 | Binary Number with Alternating Bits | Java | Easy | 2017.10.12 | Bit Manipulation | ||
| 117 | 347 | Top K Frequent Element | Java | Medium | 2017.10.14 | Hash Table, Heap | 2017.12.16 2018.2.22 2018.2.26 2018.4.24 2018.9.5 2018.10.14 2018.10.23 | |
| 118 | 692 | Top K Frequent Words | Java | Medium | 2017.10.14 | Hash Table, Heap | 2018.10.23 | |
| 119 | 657 | Judge Route Circle | Java | Easy | 2017.10.17 | String | 2018.8.16 | |
| 120 | 303 | Range Sum Query - Immutable | Java | Easy | 2017.10.18 | Dynamic Programming | 2017.12.19 2018.1.29 2018.2.22 2018.11.11 | |
| 121 | 387 | First Unique Character in a String | Java | Easy | 2017.10.19 | String | 2018.2.14 2018.4.13 2018.4.15 2018.6.30 2018.10.11 | |
| 122 | 108 | Convert Sorted Array to Binary Search Tree | Java | Easy | 2017.10.19 | Tree, DFS | 2018.1.1 | |
| 123 | 198 | House Robber | Java | Easy | 2017.10.19 | Dynamic Programming | 2017.12.5 2017.12.18 2018.1.28 2018.2.21 2018.5.24 2019.2.18 | |
| 124 | 172 | Factorial Trailing Zeroes | Java | Easy | 2017.10.20 | Math | 2018.9.15 | |
| 125 | 7 | Reverse Integer | Java | Easy | 2017.10.22 | Math | ||
| 126 | 190 | Reverse Bits | Java | Easy | 2017.10.25 | Bit Manipulation | ||
| 127 | 3 | Longest Substring Without Repeating Characters | Java | Medium | 2017.10.27 | HashTable, Two Pointers, String | 2018.1.22 2018.9.6 2018.9.21 2018.10.17 2018.10.23 2018.11.15 2019.1.10 | |
| 128 | 50 | Pow(x, n) | Java | Medium | 2017.11.1 | Math | 2018.3.19 2018.10.1 2018.11.3 2018.11.7 2018.11.12 | |
| 129 | 374 | Guess Number Higher or Lower | Java | Easy | 2017.11.2 | Binary Search | 2018.3.22 2018.10.12 2019.2.25 | |
| 130 | 242 | Valid Anagram | Java | Easy | 2017.11.4 | Hash Table, Sort | 2018.10.11 | |
| 131 | 110 | Balanced Binary Tree | Java | Easy | 2017.11.5 | Tree, DFS | 2017.12.31 2018.4.26 2018.10.14 2018.10.24 2018.11.13 | |
| 132 | 168 | Excel Sheet Column Title | Java | Easy | 2017.11.5 | Math | 2018.1.3 | |
| 133 | 11 | Container With Most Water | Java | Medium | 2017.11.7 | Array, Two Pointers | 2018.1.3 2018.9.23 | |
| 134 | 238 | Product of Array Except Self | Java | Medium | 2017.11.8 | Array | 2018.1.4 2018.4.17 2018.10.27 2018.11.9 2018.11.11 | |
| 135 | 5 | Longest Palindromic Substring | Java | Medium | 2017.11.11 | String | 2018.1.3 2018.3.19 2018.4.17 2018.9.23 | |
| 136 | 580 | Count Student Number in Departments | SQL | Medium | 2017.11.11 | Database | 2018.1.2 | |
| 137 | 243 | Shortest Word Distance | Java | Easy | 2017.11.12 | Array | 2018.1.2 | |
| 138 | 661 | Image Smoother | Java | Easy | 2017.11.12 | Array | 2018.1.3 | |
| 139 | 586 | Customer Placing the Largest Number of Orders | SQL | Easy | 2017.11.12 | Database | ||
| 140 | 595 | Big Countries | SQL | Easy | 2017.11.12 | Database | 2018.2.5 | |
| 141 | 339 | Nested List Weight Sum | Java | Easy | 2017.11.13 | DFS | 2018.1.8 2018.2.19 2018.10.4 2018.10.19 | |
| 142 | 728 | Self Dividing Numbers | Java | Easy | 2017.11.20 | Math | ||
| 143 | 346 | Moving Average from Data Stream | Java | Easy | 2017.11.20 | Design, Queue | 2018.10.6 2018.10.28 | |
| 144 | 266 | Palindrome Permutation | Java | Easy | 2017.11.20 | HashMap | 2018.10.10 2018.10.19 | |
| 145 | 682 | Baseball Game | Java | Easy | 2017.11.20 | Stack | 2018.4.10 | |
| 146 | 669 | Trim a Binary Search Tree | Java | Easy | 2017.11.20 | Tree | ||
| 147 | 293 | Flip Game | Java | Easy | 2017.11.21 | String | ||
| 148 | 637 | Average of Levels in Binary Tree | Java | Easy | 2017.11.21 | Tree | ||
| 149 | 696 | Count Binary Substrings | Java | Easy | 2017.11.22 | String | ||
| 150 | 717 | 1-bit and 2-bit Characters | Java | Easy | 2017.11.24 | Array | ||
| 151 | 653 | Two Sum IV | Java | Easy | 2017.11.24 | Tree | 2017.12.13 2018.4.19 2019.2.17 | |
| 152 | 252 | Meeting Rooms | Java | Easy | 2017.11.25 | Sort | 2018.10.11 2018.10.26 | |
| 153 | 504 | Base 7 | Java | Easy | 2017.11.25 | Math | 2018.2.3 | |
| 154 | 477 | Total Hamming Distance | Java | Easy | 2017.11.25 | Math, Bit manipulation | ||
| 155 | 112 | Path Sum | Java | Easy | 2017.11.25 | Tree, DFS | 2018.3.15 2018.5.6 | |
| 156 | 734 | Sentence Similarity | Java | Easy | 2017.11.25 | Hash Table | 2018.9.12 | |
| 157 | 733 | Flood Fill | Java | Easy | 2017.11.25 | DFS | 2018.10.11 2019.4.12 | |
| 158 | 735 | Asteroid Collision | Java | Medium | 2017.11.26 | Stack | ||
| 159 | 170 | Two Sum III | Java | Easy | 2017.11.26 | Hash Table, Design | 2017.12.13 2018.10.16 2019.1.11 2019.2.17 | |
| 160 | 256 | Paint House | Java | Easy | 2017.11.27 | Dynamic Programming | 2017.12.19 2018.1.28 2018.2.21 2018.5.23 | |
| 161 | 342 | Power of Four | Java | Easy | 2017.11.27 | Bit Manipulation | ||
| 162 | 231 | Power of Two | Java | Easy | 2017.11.27 | Math, Bit Manipulation | ||
| 163 | 326 | Power of Three | Java | Easy | 2017.11.27 | Math | ||
| 164 | 654 | Maximum Binary Tree | Java | Medium | 2017.11.27 | Stack | 2018.11.17 | |
| 165 | 191 | Number of 1 Bits | Java | Easy | 2017.11.27 | Bit manipulation | 2018.7.14 2018.9.8 | |
| 166 | 624 | Maximum Distance in Arrays | Java | Easy | 2017.11.27 | Array | ||
| 167 | 197 | Rising Temperature | SQL | Easy | 2017.11.27 | Database | ||
| 168 | 96 | Unique Binary Search Trees | Java | Easy | 2017.11.28 | Dynamic Programming, Tree | 2017.12.19 2017.12.31 2018.5.9 2018.10.3 | |
| 169 | 338 | Counting Bits | Java | Medium | 2017.11.29 | Dynamic Programming, Bit manipulation | 2017.12.18 2019.1.27 | |
| 170 | 257 | Binary Tree Paths | Java | Easy | 2017.11.29 | Tree, DFS | 2018.10.12 2018.10.24 2018.11.11 | |
| 171 | 404 | Sum of Left Leaves | Java | Easy | 2017.11.29 | Tree | 2018.3.5 2018.4.2 2019.3.1 | |
| 172 | 739 | Daily Temperatures | Java | Medium | 2017.12.2 | Stack | 2017.12.4 2019.2.27 | |
| 173 | 738 | Monotone Incresing Digits | Java | Medium | 2017.12.2 | Greedy | 2017.12.4 | |
| 174 | 6 | ZigZag Conversion | Java | Medium | 2017.12.7 | String | 2018.9.23 | |
| 175 | 15 | 3Sum | Java | Medium | 2017.12.7 | Array, Two Pointers | 2018.3.26 2018.3.28 2018.3.29 2018.9.23 2018.10.25 2018.11.10 2019.2.17 | |
| 176 | 16 | 3Sum Closest | Java | Medium | 2017.12.8 | Array, Two Pointers | 2018.3.29 2018.9.23 2019.2.17 | |
| 177 | 259 | 3Sum Smaller | Java | Medium | 2017.12.8 | Array, Two Pointers | 2018.3.29 2018.11.26 2019.2.17 | |
| 178 | 18 | 4Sum | Java | Medium | 2017.12.8 | Array, Two Pointers | 2018.9.24 2019.2.17 | |
| 179 | 454 | 4Sum II | Java | Medium | 2017.12.8 | Array, Hash Table | ||
| 180 | 287 | Find the Duplicate Number | Java | Medium | 2017.12.8 | Array, Two Pointers, Binary Search | 2018.3.31 2018.4.17 2018.11.7 | |
| 181 | 80 | [Remove Duplicates from Sorted Array II][80] | Java | Medium | 2017.12.8 | Array, Two Pointers | 2018.10.2 | |
| 182 | 107 | Binary Tree Level Order Traversal II | Java | Easy | 2017.12.9 | Tree, BFS | 2018.2.13 2018.3.15 2018.4.24 2018.5.29 | |
| 183 | 278 | First Bad Version | Java | Easy | 2017.12.9 | Binary Search | 2018.3.22 2018.10.16 | |
| 184 | 744 | [Find Smallest Letter Greater Than Target][744] | Java | Easy | 2017.12.9 | |||
| 185 | 17 | Letter Combinations of a Phone Number | Java | Medium | 2017.12.10 | String, Backtracking | 2018.4.24 2018.9.24 2018.10.27 2018.11.12 2018.12.5 | |
| 186 | 151 | Reverse Words in a String | Java | Medium | 2017.12.10 | String | 2018.2.16 2018.10.26 | |
| 187 | 186 | Reverse Words in a String II | Java | Medium | 2017.12.10 | String | 2018.2.16 2018.4.16 | |
| 188 | 22 | Generate Parentheses | Java | Medium | 2017.12.10 | String, Backtracking | 2018.9.24 2018.10.28 | |
| 189 | 437 | Path Sum III | Java | Easy | 2017.12.10 | Tree | 2018.5.6 2018.10.14 2018.11.18 | |
| 190 | 458 | Poor Pigs | Java | Easy | 2017.12.11 | Math | ||
| 191 | 720 | Longest Word in Dictionary | Java | Easy | 2017.12.12 | HashTable, Trie | ||
| 192 | 538 | Convert BST to Greater Tree | Java | Easy | 2017.12.12 | Tree | ||
| 193 | 544 | Output Contest Matches | Java | Medium | 2017.12.12 | String | ||
| 194 | 419 | Battleships in a Board | Java | Medium | 2017.12.12 | Array | 2018.5.23 | |
| 195 | 415 | Add Strings | Java | Easy | 2017.12.13 | Math | 2018.10.14 2018.11.12 | |
| 196 | 208 | Implement Trie (Prefix Tree) | Java | Medium | 2017.12.14 | Design Trie | ||
| 197 | 211 | Add and Search Word - Data structure design | Java | Medium | 2017.12.14 | Backtracking, Design, Trie | 2018.10.22 2018.11.11 | |
| 198 | 369 | Plus One Linked List | Java | Medium | 2017.12.14 | Linked List | 2018.2.8 2018.2.11 | |
| 199 | 104 | Maximum Depth of Binary Tree | Java | Easy | 2017.12.15 | Tree, DFS | 2017.12.30 2018.1.5 2018.2.17 2018.10.15 | |
| 200 | 202 | Happy Number | Java | Easy | 2017.12.15 | Hash Table, Math | ||
| 201 | 725 | Split Linked List in Parts | Java | Medium | 2017.12.16 | Linked List | 2018.12.5 | |
| 202 | 215 | Kth Largest Element in an Array | Java | Medium | 2017.12.16 | Divide and Conquer, Heap | 2018.4.2 2018.10.18 2018.11.11 2019.1.14 2019.2.18 2019.2.27 | |
| 203 | 748 | Shortest Completing Word | Java | Easy | 2017.12.16 | Hash Table | ||
| 204 | 740 | Delete and Earn | Java | Medium | 2017.12.6 | Dynamic Programming | 2017.12.17 2018.1.9 | |
| 205 | 746 | Min Cost Climbing Stairs | Java | Easy | 2017.12.17 | Dynamic Programming | 2018.1.27 2018.2.21 2018.4.12 2018.5.1 2018.5.23ff | |
| 206 | 276 | Paint House | Java | Easy | 2017.12.17 | Dynamic Programming | 2018.1.29 | |
| 207 | 91 | Decode Ways | Java | Medium | 2017.12.18 | Dynamic Programming | 2018.10.3 2018.10.10 2018.10.27 2018.11.11 2018.11.17 2019.2.27 | |
| 208 | 213 | House Robber II | Java | Medium | 2017.12.19 | Dynamic Programming | 2018.11.10 2019.2.18 | |
| 209 | 337 | House Robber III | Java | Medium | 2017.12.19 | Dynamic Programming | 2018.11.10 | |
| 210 | 647 | Palindromic Substrings | Java | Medium | 2017.12.19 | Dynamic Programming | ||
| 211 | 413 | Arithmetic Slices | Java | Medium | 2017.12.20 | Dynamic Programming | ||
| 212 | 712 | Minimum ASCII Delete Sum for Two Strings | Java | Medium | 2017.12.20 | Dynamic Programming | ||
| 213 | 357 | Count Numbers with Unique Digits | Java | Medium | 2017.12.20 | Dynamic Programming | ||
| 214 | 62 | Unique Paths | Java | Medium | 2017.12.20 | Dynamic Programming | 2018.1.30 2018.3.7 2018.10.2 2019.1.16 2019.3.8 | |
| 215 | 63 | Unique Paths II | Java | Medium | 2017.12.20 | Dynamic Programming | 2018.1.30 2018.3.7 2018.6.9 2018.10.2 2019.3.9 | |
| 216 | 64 | Minimum Path Sum | Java | Medium | 2017.12.21 | Dynamic Programming | 2018.10.1 2018.10.13 2019.3.9 | |
| 217 | 120 | Triangle | Java | Medium | 2017.12.21 | Dynamic Programming | ||
| 218 | 139 | Word Break | Java | Medium | 2017.12.21 | Dynamic Programming | 2018.5.17 2018.5.26 2019.2.17 | |
| 219 | 258 | Add Digits | Java | Easy | 2016.3.21 | Math | 2017.12.21 2018.6.30 | |
| 220 | 401 | Binary Watch | Java | Easy | 2017.12.21 2017.12.22 | Bit manipulation Backtracking | ||
| 221 | 52 | N-Queens II | Java | Hard | 2017.12.22 | Backtracking | ||
| 222 | 51 | N-Queens | Java | Hard | 2017.12.22 | Backtracking | ||
| 223 | 152 | Maximum Product Subarray | Java | Medium | 2017.12.22 | Dynamic Programming | 2018.4.29 2019.1.10 2019.3.8 | |
| 224 | 474 | [Ones and Zeroes][474] | Java | Medium | 2017.12.23 | Dynamic Programming | 2019.2.14 | |
| 225 | 79 | Word Search | Java | Medium | 2017.12.25 | Array, Backtracking | 2018.5.25 2018.10.2 2018.11.9 2019.2.20 | |
| 226 | 674 | Longest Continuous Increasing Subsequence | Java | Easy | 2017.12.25 | Array | 2018.10.12 2018.11.3 2018.11.6 2018.11.12 2019.3.8 | |
| 227 | 175 | Combine Two Tables | SQL | Easy | 2017.12.27 | DataBase | ||
| 228 | 176 | Second Highest Salary | SQL | Easy | 2017.12.27 | DataBase | ||
| 229 | 177 | Nth Highest Salary | SQL | Medium | 2017.12.27 | DataBase | ||
| 230 | 178 | Rank Scores | SQL | Medium | 2017.12.27 | DataBase | ||
| 231 | 180 | Consecutive Numbers | SQL | Medium | 2017.12.27 | DataBase | ||
| 232 | 181 | Employees Earning More Than Their Managers | SQL | Easy | 2017.12.27 | DataBase | ||
| 233 | 182 | Duplicate Emails | SQL | Easy | 2017.12.27 | DataBase | ||
| 234 | 183 | Customers Who Never Order | SQL | Easy | 2017.12.27 | DataBase | ||
| 235 | 184 | Department Highest Salary | SQL | Medium | 2017.12.27 | DataBase | ||
| 236 | 677 | Map Sum Pairs | Java | Medium | 2017.12.28 | Trie | ||
| 237 | 676 | Implement Magic Dictionary | Java | Medium | 2017.12.29 | Trie | ||
| 238 | 185 | Department Top Three Salaries | SQL | Hard | 2017.12.29 | DataBase | ||
| 239 | 196 | Delete Duplicate Emails | SQL | Easy | 2017.12.29 | DataBase | ||
| 240 | 627 | Swap Salary | SQL | Easy | 2017.12.29 | DataBase | ||
| 241 | 648 | Replace Words | Java | Medium | 2017.12.29 | Trie | ||
| 242 | 421 | Maximum XOR of Two Numbers in an Array | Java | Medium | 2017.12.30 | Bit Manipulation | ||
| 243 | 620 | Not Boring Movies | SQL | Easy | 2017.12.30 | DataBase | ||
| 244 | 619 | Biggest Single Number | SQL | Easy | 2017.12.30 | DataBase | ||
| 245 | 226 | Invert Binary Tree | Java | Easy | 2017.12.30 | Tree | 2018.1.11 2018.2.5 2018.5.7 2018.5.16 2018.11.18 | |
| 246 | 235 | Lowest Common Ancestor of a Binary Search Tree | Java | Easy | 2017.12.31 | Tree | 2018.4.12 2018.7.19 2018.9.16 2018.10.24 | |
| 247 | 613 | Shortest Distance in a Line | SQL | Easy | 2017.12.31 | DataBase | ||
| 248 | 577 | Employee Bonus | SQL | Easy | 2017.12.31 | DataBase | ||
| 249 | 584 | Find Customer Referee | SQL | Easy | 2017.12.31 | DataBase | ||
| 250 | 124 | Binary Tree Maximum Path Sum | Java | Hard | 2018.1.1 | Tree | 2018.2.9 2018.11.11 | |
| 251 | 244 | Shortest Word Distance II | Java | Medium | 2018.1.2 | HashTable, Array | ||
| 252 | 245 | Shortest Word Distance III | Java | Medium | 2018.1.2 | Array | ||
| 253 | 229 | Majority Element II | Java | Medium | 2018.1.6 | Array | 2018.3.2 | |
| 254 | 570 | Managers with at Least 5 Direct Reports | SQL | Medium | 2018.1.6 | DataBase | ||
| 255 | 596 | Classes More Than 5 Students | SQL | Easy | 2018.1.6 | DataBase | ||
| 256 | 56 | Merge Intervals | Java | Medium | 2018.1.6 | Array | 2018.2.16 2018.4.23 2018.10.1 2018.10.27 2018.11.11 | |
| 257 | 610 | Triangle Judgement | SQL | Easy | 2018.1.9 | DataBase | ||
| 258 | 607 | Sales Person | SQL | Easy | 2018.1.11 | DataBase | ||
| 259 | 556 | Next Greater Element III | Java | Medium | 2018.1.13 | String | 2018.11.3 | LC31 Next Permutation |
| 260 | 72 | Edit Distance | Java | Hard | 2018.1.18 | Dynamic Programming | 2019.1.15 | |
| 261 | 283 | Move Zeroes | Java | Easy | 2018.1.18 | Array, Two Pointers | 2018.10.11 2018.11.11 | |
| 262 | 766 | Toeplitz Matrix | Java | Easy | 2018.1.21 | Array | ||
| 263 | 769 | Max Chunks To Make Sorted | Java | Medium | 2018.1.21 | Array | ||
| 264 | 76 | Minimum Window Substring | Java | Hard | 2018.1.23 | HashTable, Two Pointers, String | 2018.10.26 | |
| 265 | 159 | Longest Substring with At Most Two Distinct Characters | Java | Hard | 2018.1.23 | HashTable, Two Pointers, String | 2018.10.18 | |
| 266 | 340 | Longest Substring with At Most K Distinct Characters | Java | Hard | 2018.1.23 | HashTable, Two Pointers, String | 2018.10.18 2018.10.27 2018.11.15 | |
| 267 | 697 | Degree of an Array | Java | Easy | 2018.1.23 | Array | ||
| 268 | 608 | Tree Node | SQL | Medium | 2018.1.25 | DataBase | 2018.3.30 | |
| 269 | 775 | Global and Local Inversions | Java | Medium | 2018.1.29 | Array, Math | ||
| 270 | 750 | Number of Corner Rectangles | Java | Medium | 2018.1.30 | Dynamic Programming | 2018.2.21 | |
| 271 | 42 | Trapping Rain Water | Java | Hard | 2018.1.30 | Array, Dynamic Programming, Two pointers, Stack | 2018.10.22 2019.1.28 | |
| 272 | 217 | Contains Duplicate | Java | Easy | 2018.2.2 | Array, HashMap | 2018.2.14 | |
| 273 | 537 | Complex Number Multiplication | Java | Medium | 2018.2.4 | String, Math | ||
| 274 | 598 | Range Addition II | Java | Easy | 2018.2.5 | Math | ||
| 275 | 771 | Jewels and Stones | Java | Easy | 2018.2.5 | Hash Table | 2018.2.24 2018.4.9 | |
| 276 | 779 | K-th Symbol in Grammar | Java | Medium | 2018.2.7 | Recursion | ||
| 277 | 783 | Minimum Distance Between BST Nodes | Java | Easy | 2018.2.10 | Tree | ||
| 278 | 781 | Rabbits in Forrest | Java | Medium | 2018.2.10 | HashTable | ||
| 279 | 300 | [Longest Increasing Subsequence][300] | Java | Medium | 2018.2.11 | Binary Search, Dynamic Programming | 2018.2.23 2018.3.2 2018.11.12 2019.1.27 2019.2.14 | |
| 280 | 143 | Reorder List | Java | Medium | 2018.2.12 | LinkedList | 2018.8.9 2018.10.28 2018.11.11 | |
| 281 | 379 | Design Phone Directory | Java | Medium | 2018.2.12 | LinkedList, Design | 2018.11.17 | |
| 282 | 102 | Binary Tree Level Order Traversal | Java | Medium | 2018.2.13 | Tree, BFS | 2018.4.14 2018.4.17 2018.4.24 2018.6.1 2018.9.15 2018.10.3 | |
| 283 | 138 | Copy List with Random Pointer | Java | Medium | 2018.2.13 | LinkedList, HashTable | 2018.10.6 2018.10.27 2019.1.12 | |
| 284 | 161 | One Edit Distance | Java | Medium | 2018.2.20 | String | 2018.10.27 2019.1.15 | |
| 285 | 384 | Shuffle an Array | Java | Medium | 2018.2.21 | Design | ||
| 286 | 364 | Nested List Weight Sum II | Java | Medium | 2018.2.22 | DFS | 2019.3.15 | |
| 287 | 103 | Binary Tree Zigzag Level Order Traversal | Java | Medium | 2018.2.22 | BFS, Tree | 2018.4.24 2018.10.3 2018.10.24 | |
| 288 | 516 | Longest Palindromic Subsequence | Java | Medium | 2018.2.23 | Dynamic Programming | 2018.3.19 2019.2.9 | |
| 289 | 322 | Coin Change | Java | Medium | 2018.2.24 | Dynamic Programming | 2019.1.16 2019.2.28 2019.3.8 | |
| 290 | 75 | Sort Colors | Java | Medium | 2018.2.28 | Sort | 2018.4.4 2018.10.2 | |
| 291 | 435 | Non-overlapping Intervals | Java | Medium | 2018.2.28 | Greedy | ||
| 292 | 134 | Gas Station | Java | Medium | 2018.3.1 | Greedy | 2019.2.17 | |
| 293 | 518 | Coin Change 2 | Java | Medium | 2018.3.1 | Dynamic Programming | ||
| 294 | 723 | Longest Continuous Increasing Subsequence | Java | Easy | 2018.3.1 | Array | ||
| 295 | 200 | Number of Islands | Java | Medium | 2018.3.4 | DFS, BFS, Union-find | 2018.4.4 2018.11.12 2019.1.12 | |
| 296 | 543 | Diameter of Binary Tree | Java | Easy | 2018.3.6 | DFS, Tree | 2018.10.12 2018.10.24 2018.11.11 | |
| 297 | 671 | Second Minimum Node In a Binary Tree | Java | Easy | 2018.3.6 | BFS, Tree | 2018.5.25 | |
| 298 | 270 | Closest Binary Search Tree Value | Java | Easy | 2018.3.6 | Binary Search, Tree | 2018.3.8 2018.6.11 2018.7.9 2018.10.14 2018.10.24 2018.11.13 | |
| 299 | 563 | Binary Tree Tilt | Java | Easy | 2018.3.8 | Tree | ||
| 300 | 572 | Subtree of Another Tree | Java | Easy | 2018.3.8 | Tree | 2018.4.23 2018.10.24 | |
| 301 | 501 | Find Mode in Binary Search Tree | Java | Easy | 2018.3.9 | Tree | ||
| 302 | 687 | Longest Univalue Path | Java | Easy | 2018.3.10 | Tree | ||
| 303 | 513 | Find Bottom Left Tree Value | Java | Medium | 2018.3.12 | Tree | 2018.5.30 | |
| 304 | 366 | Find Leaves of Binary Tree | Java | Medium | 2018.3.13 | Tree | ||
| 305 | 796 | Rotate String | Java | Easy | 2018.3.14 | String | ||
| 306 | 515 | Find Largest Value in Each Tree Row | Java | Medium | 2018.3.14 | Tree | 2018.5.30 | |
| 307 | 250 | Count Univalue Subtrees | Java | Medium | 2018.3.16 | Tree | ||
| 308 | 280 | Wiggle Sort | Java | Medium | 2018.3.20 | Array, Sort | 2018.5.23 | |
| 309 | 116 | Populating Next Right Pointers in Each Node | Java | Medium | 2018.3.21 | Tree | ||
| 310 | 33 | Search in Rotated Sorted Array | Java | Medium | 2018.3.22 | Binary Search | 2018.3.27 2018.4.24 2018.9.29 2018.10.10 2018.10.26 2018.11.7 2018.11.12 | |
| 311 | 162 | Find Peak Element | Java | Medium | 2018.3.23 | Binary Search | 2018.8.17 2018.11.6 2019.2.24 | |
| 312 | 658 | Find K Closest Elements | Java | Medium | 2018.3.27 | Binary Search, Two Pointers | 2018.8.2 2018.8.17 2018.10.27 | |
| 313 | 127 | Word Ladder | Java | Medium | 2018.4.6 | BFS | 2018.4.14 2018.4.23 2018.5.26 2018.6.25 2018.11.13 2019.2.20 | |
| 314 | 207 | Course Schedule | Java | Medium | 2018.4.6 | Topological Sort | 2018.6.6 2018.11.13 | |
| 315 | 210 | Course Schedule II | Java | Medium | 2018.4.7 | Topological Sort | 2018.4.10 2018.6.6 2018.11.13 | |
| 316 | 78 | Subsets | Java | Medium | 2018.4.7 | DFS | 2018.4.13 2018.10.1 2018.10.13 2018.10.26 | |
| 317 | 31 | Next Permutation | Java | Medium | 2018.4.8 | Array | 2018.11.10 | |
| 318 | 46 | Permutations | Java | Medium | 2018.4.8 | Backtracking | 2018.7.12 2018.10.1 2018.10.27 | |
| 319 | 716 | Max Stack | Java | Hard | 2018.4.11 | Stack, Design | ||
| 320 | 451 | Sort Character By Frequency | Java | Medium | 2018.4.11 | Heap, HashMap | ||
| 321 | 98 | Validate Binary Search Tree | Java | Medium | 2018.4.11 | DFS, Tree | 2018.4.21 2018.10.23 2018.11.11 2018.11.13 | |
| 322 | 763 | Partition Labels | Java | Medium | 2018.4.11 | Greedy, Two Pointers | ||
| 323 | 236 | Lowest Common Ancestor of a Binary Tree | Java | Medium | 2018.4.12 | Tree | 2018.9.16 2018.10.24 | |
| 324 | 133 | Clone Graph | Java | Medium | 2018.4.12 | Graph, DFS, BFS | 2018.10.27 | |
| 325 | 535 | Encode and Decode TinyURL | Java | Medium | 2018.4.13 | HashTable, Math | ||
| 326 | 817 | Linked List Components | Java | Medium | 2018.4.14 | Linked List | 2018.6.21 | |
| 327 | 23 | Merge k Sorted Lists | Java | Hard | 2018.4.15 | Linked List, Heap | 2018.4.17 2018.7.7 2018.7.11 2018.10.28 | |
| 328 | 325 | Maximum Size Subarray Sum Equals k | Java | Medium | 2018.4.16 | HashMap | 2018.5.14 2018.10.28 2018.11.12 | |
| 329 | 165 | Compare Version Numbers | Java | Medium | 2018.4.16 | String | ||
| 330 | 285 | Inorder Successor in BST | Java | Medium | 2018.4.17 | Tree | 2018.10.24 | |
| 331 | 323 | Number of Connected Components in an Undirected Graph | Java | Medium | 2018.4.20 | Union Find, DFS, BFS, Graph | 2018.5.30 | |
| 332 | 48 | Rotate Image | Java | Medium | 2018.4.23 | Array | 2018.10.1 2018.11.5 | |
| 333 | 680 | Valid Palindrome II | Java | Easy | 2018.4.24 | String | 2018.10.15 2018.10.26 2018.11.10 | |
| 334 | 560 | Subarray Sum Equals K | Java | Medium | 2018.4.24 | Array, Hash Table | 2018.10.28 2018.11.10 | |
| 335 | 39 | Combination Sum | Java | Medium | 2018.4.24 | Array, Backtracking | 2018.10.1 2018.10.25 2019.2.5 2019.2.24 | |
| 336 | 40 | Combination Sum II | Java | Medium | 2018.4.24 | Array, Backtracking | 2018.10.1 2018.10.27 2019.2.5 2019.2.24 | |
| 337 | 153 | Find Minimum in Rotated Sorted Array | Java | Medium | 2018.4.26 | Array, Binary Search | 2018.8.17 2018.11.7 | |
| 338 | 114 | Flatten Binary Tree to Linked List | Java | Medium | 2018.4.27 | Tree, DFS | 2018.11.13 | |
| 339 | 824 | Goat Latin | Java | Easy | 2018.5.2 | String | 2018.10.10 2018.10.19 | |
| 340 | 444 | Sequence Reconstruction | Java | Medium | 2018.5.3 | Graph, Topological Sort | ||
| 341 | 397 | Integer Replacement | Java | Medium | 2018.5.3 | Math, Bit Manipulation | ||
| 342 | 137 | [Single Number II][137] | Java | Medium | 2018.5.4 | HashTable, Bit Manipulation、 | 2018.10.30 | |
| 343 | 742 | Closest Leaf in a Binary Tree | Java | Medium | 2018.5.5 | Tree | ||
| 344 | 113 | Path Sum II | Java | Medium | 2018.5.6 | Tree, DFS | ||
| 345 | 95 | Unique Binary Search Tree II | Java | Medium | 2018.5.9 | Tree, Divide and Conquar | ||
| 346 | 199 | Binary Tree Right Side View | Java | Medium | 2018.5.10 | Tree, BFS, DFS | 2018.6.1 2018.10.24 2018.11.5 2018.11.11 | |
| 347 | 370 | Range Addition | Java | Meidum | 2018.5.11 | Array | ||
| 348 | 406 | Queue Reconstruction by Height | Java | Medium | 2018.5.11 | Greedy | ||
| 349 | 531 | [Lonely Pixel I][531] | Java | Medium | 2018.5.11 | Array, DFS | ||
| 350 | 281 | Zigzag Iterator | Java | Medium | 2018.5.12 | Design | 2018.11.17 | |
| 351 | 530 | Minimum Absolute Difference in BST | Java | Easy | 2018.5.13 | Binary Search Tree | ||
| 352 | 506 | Relative Ranks | Java | Easy | 2018.5.14 | Array | ||
| 353 | 298 | Binary Tree Longest Consecutive Sequence | Java | Medium | 2018.5.14 | Tree | 2019.2.11 | |
| 354 | 378 | Kth Smallest Element in a Sorted Matrix | Java | Medium | 2018.5.15 | Binary Search, Heap | 2018.10.18 | |
| 355 | 665 | Non-decreasing Array | Java | Easy | 2018.5.15 | Array | ||
| 356 | 686 | Repeated String Match | Java | Easy | 2018.5.17 | String | 2018.5.18 | |
| 357 | 422 | Valid Word Square | Java | Easy | 2018.5.17 | String | ||
| 358 | 361 | Bomb Enemy | Java | Medium | 2018.5.17 | Dynamic Programming | ||
| 359 | 482 | License Key Formating | Java | Easy | 2018.5.18 | String | ||
| 360 | 246 | Strobogrammatic Number | Java | Easy | 2018.5.19 | Hash Table, Math | 2018.10.14 2018.11.12 | |
| 361 | 838 | Push Dominoes | Java | Medium | 2018.5.20 | String | ||
| 362 | 836 | Rectangle Overlap | Java | Easy | 2018.5.20 | Math | ||
| 363 | 507 | Perfect Number | Java | Easy | 2018.5.20 | Math | ||
| 364 | 784 | Letter Case Permutation | Java | Easy | 2018.5.21 | Backtracking | ||
| 365 | 443 | String Compression | Java | Easy | 2018.5.21 | String | 2018.10.28 | |
| 366 | 408 | Valid Word Abbreviation | Java | Easy | 2018.5.21 | String | 2018.10.26 2018.11.17 | |
| 367 | 724 | Find Pivot Index | Java | Easy | 2018.5.21 | Array | ||
| 368 | 633 | Sum Of Square Numbers | Java | Easy | 2018.5.22 | Math | ||
| 369 | 367 | Valid Perfect Square | Java | Easy | 2018.5.22 | Math, Binary Search | ||
| 370 | 405 | Convert a Number to Hexadecimal | Java | Easy | 2018.5.22 | Bit Manipulation | ||
| 371 | 767 | Reorganize String | Java | Medium | 2018.5.23 | String, Heap, Greedy, Sort | 2019.3.6 | |
| 372 | 441 | Arranging Coins | Java | Easy | 2018.5.24 | Math, Binary Search | ||
| 373 | 255 | Verify Preorder Sequence in Binary Search Tree | Java | Medium | 2018.5.26 | Stack, Tree | ||
| 374 | 841 | Keys and Rooms | Java | Medium | 2018.5.27 | DFS, Graph | ||
| 375 | 813 | Largest Sum of Averages | Java | Medium | 2018.5.28 | Dynamic Programming | ||
| 376 | 490 | The Maze | Java | Medium | 2018.5.31 | BFS, DFS | 2019.3.3 | |
| 377 | 752 | Open the lock | Java | Medium | 2018.6.1 | BFS | 2018.6.4 2018.6.13 2019.2.16 | |
| 378 | 505 | The Maze II | Java | Medium | 2018.6.2 | BFS, Heap | 2019.3.3 | |
| 379 | 844 | Backspace String Compare | Java | Easy | 2018.6.3 | Two Pointers, Stack | 2019.2.17 2019.2.27 | |
| 380 | 845 | Longest Mountain in Array | Java | Medium | 2018.6.3 | Two Pointers | 2018.9.20 2019.2.18 | |
| 381 | 846 | Hand of Straights | Java | Medium | 2018.6.6 | Map | 2018.6.14 | |
| 382 | 729 | My Calendar I | Java | Medium | 2018.6.7 | TreeMap | 2018.6.13 2018.10.27 2019.3.3 | |
| 383 | 731 | My Calendar II | Java | Medium | 2018.6.7 | TreeMap | 2018.6.14 | |
| 384 | 271 | Encode and Decode Strings | Java | Medium | 2018.6.9 | String | 2018.6.13 | |
| 385 | 849 | Maximize Distance to Closest Person | Java | Easy | 2018.6.10 | Array | ||
| 386 | 848 | Shifting Letters | Java | Medium | 2018.6.10 | String | ||
| 387 | 851 | Loud and Rich | Java | Medium | 2018.6.10 | DFS | ||
| 388 | 297 | Serialize and Deserialize Binary Tree | Java | Hard | 2018.6.12 | Tree, Design | 2018.6.13 2018.10.24 | |
| 389 | 826 | Most Profit Assigning Work | Java | Medium | 2018.6.12 | Two Pointers | 2018.6.13 2018.8.10 | |
| 390 | 842 | [Split Array into Fibonacci Sequence][842] | Java | Medium | 2018.6.14 | String, Backtracking, Greedy | 2018.6.15 | |
| 391 | 604 | Design Compressed String Iterator | Java | Easy | 2018.6.16 | Design | ||
| 392 | 852 | Peak Index in a Mountain Array | Java | Easy | 2018.6.17 | Binary Search | ||
| 393 | 853 | Car Fleet | Java | Medium | 2018.6.17 | Array | 2019.2.17 | |
| 394 | 855 | Exam Room | Java | Medium | 2018.6.17 | Design | 2018.6.19 | |
| 395 | 801 | Minimum Swaps To Make Sequences Increasing | Java | Medium | 2018.6.18 | Dynamic Programming | 2018.6.19 | |
| 396 | 126 | Word Ladder II | Java | Hard | 2018.6.23 | BFS | 2019.2.20 | |
| 397 | 859 | Buddy Strings | Java | Easy | 2018.6.24 | String | ||
| 398 | 856 | Score of Parentheses | Java | Medium | 2018.6.24 | DFS | ||
| 399 | 825 | Friends Of Appropriate Ages | Java | Medium | 2018.6.25 | Array | ||
| 400 | 792 | Number of Matching Subsequences | Java | Medium | 2018.6.26 | Array | ||
| 401 | 583 | Delete Operation for Two Strings | Java | Medium | 2018.6.27 | String, Dynamic Programming | ||
| 402 | 146 | LRU Cache | Java | Hard | 2018.6.28 | Design | 2018.7.5 2018.8.8 2018.10.27 | |
| 403 | 4 | Median of Two Sorted Arrays | Java | Hard | 2018.6.29 | Array, Binary Search | 2018.6.30 2018.10.27 2018.11.15 2019.2.24 | |
| 404 | 860 | Lemonade Change | Java | Easy | 2018.7.1 | Array | ||
| 405 | 861 | Score After Flipping Matrix | Java | Medium | 2018.7.6 | Greedy | ||
| 406 | 867 | Transpose Matrix | Java | Easy | 2018.7.8 | Array | ||
| 407 | 866 | Smallest Subtree with all the Deepest Nodes | Java | Medium | 2018.7.8 | Tree | ||
| 408 | 47 | Permutations II | Java | Medium | 2018.7.12 | Backtracking | 2018.10.1 2018.10.27 | |
| 409 | 868 | Binary Gap | Java | Easy | 2018.7.15 | Bit Manipulation | ||
| 410 | 869 | Reordered Power of 2 | Java | Medium | 2018.7.15 | DFS, Bit Manipulation | ||
| 411 | 470 | Implement Rand10 Using Rand7 | Java | Medium | 2018.7.16 | Random, Math | ||
| 412 | 871 | Minimum Number of Refueling Stops | Java | Hard | 2018.7.16 | Dynamic Programming | 2018.8.8 | |
| 413 | 709 | To Lower Case | Java | Easy | 2018.7.21 | String | ||
| 414 | 492 | Construct the Rectangle | Java | Easy | 2018.7.21 | Array | ||
| 415 | 872 | Leaf-Similar Trees | Java | Easy | 2018.7.23 | Tree | ||
| 416 | 874 | Walking Robot Simulation | Java | Easy | 2018.7.23 | Array | ||
| 417 | 873 | Length of Longest Fibonacci Subsequence | Java | Medium | 2018.7.24 | Dynamic Programming, Array | ||
| 418 | 875 | Koko Eating Bananas | Java | Medium | 2018.7.24 | Binary Search | ||
| 419 | 540 | Single Element in a Sorted Array | Java | Medium | 2018.7.25 | Array | ||
| 420 | 700 | Search in a Binary Search Tree | Java | Easy | 2018.7.26 | Tree | ||
| 421 | 429 | N-ary Tree Level Order Traversal | Java | Easy | 2018.7.26 | Tree, BFS | 2019.2.10 | |
| 422 | 528 | Random Pick with Weight | Java | Medium | 2018.7.30 | Binary Search, Random | ||
| 423 | 876 | Middle of the Linked List | Java | Easy | 2018.7.30 | Linked List | 2018.10.18 | |
| 424 | 877 | Stone Game | Java | Medium | 2018.7.30 | Math, Dynamic Programming | 2018.11.9 | |
| 425 | 478 | Generate Random Point in a Circle | Java | Medium | 2018.7.31 | Math, Random, Rejection Sampling | ||
| 426 | 704 | Binary Search | Java | Easy | 2018.8.1 | Binary Search | ||
| 427 | 123 | Best Time to Buy and Sell Stock III | Java | Hard | 2018.8.2 | Dynamic Programming, Array | 2019.1.28 2019.2.12 | |
| 428 | 809 | Expressive Words | Java | Medium | 2018.8.3 | String | 2019.2.10 | |
| 429 | 887 | Projection Area of 3D Shapes | Java | Easy | 2018.8.5 | Math | ||
| 430 | 881 | Boats to Save People | Java | Medium | 2018.8.5 | Greedy, Two Pointers | 2018.8.15 | |
| 431 | 880 | Decoded String at Index | Java | Medium | 2018.8.7 | String | ||
| 432 | 673 | Number of Longest Increasing Subsequence | Java | Medium | 2018.8.9 | Dynamic Programming | ||
| 433 | 884 | Uncommon Words from Two Sentences | Java | Easy | 2018.8.15 | Hash Table | ||
| 434 | 179 | Largest Number | Java | Meidum | 2018.8.19 | Sort | 2018.9.15 | |
| 435 | 888 | Fair Candy Swap | Java | Easy | 2018.8.19 | Array | ||
| 436 | 889 | Construct Binary Tree from Preorder and Postorder Traversal | Java | Medium | 2018.8.20 | Tree | ||
| 437 | 890 | Find and Replace Pattern | Java | Medium | 2018.8.20 | String | 2019.2.27 | |
| 438 | 886 | Possible Bipartition | Java | Medium | 2018.8.21 | DFS | ||
| 439 | 885 | Spiral Matrix III | Java | Medium | 2018.8.22 | Math | 2018.10.22 | |
| 440 | 703 | Kth Largest Element in a Stream | Java | Easy | 2018.8.22 | Heap | 2018.10.18 2019.2.18 | |
| 441 | 559 | Maximum Depth of N-ary Tree | Java | Easy | 2018.8.23 | Tree, DFS, BFS | ||
| 442 | 589 | N-ary Tree Preorder Traversal | Java | Easy | 2018.8.24 | Tree | ||
| 443 | 590 | N-ary Tree Postorder Traversal | Java | Easy | 2018.8.24 | Tree | ||
| 444 | 892 | Surface Area of 3D Shapes | Java | Easy | 2018.8.27 | Math | ||
| 445 | 893 | Groups of Special-Equivalent Strings | Java | Easy | 2018.8.28 | String | ||
| 446 | 894 | All Possible Full Binary Trees | Java | Medium | 2018.8.28 | Tree | ||
| 447 | 253 | Meeting Rooms II | Java | Medium | 2018.8.29 | Heap, Greedy, Sort | 2018.10.19 2018.10.26 2018.11.10 2019.1.7 2019.1.14 | |
| 448 | 54 | Spiral Matrix | Java | Medium | 2018.8.29 | Array | 2018.10.1 2018.10.22 | |
| 449 | 59 | Spiral Matrix II | Java | Medium | 2018.8.29 | Array | 2018.10.1 2018.10.22 | |
| 450 | 681 | Next Closest Time | Java | Medium | 2018.8.30 | String | 2019.1.15 | |
| 451 | 49 | Group Anagrams | Java | Medium | 2018.8.31 | HashTable | 2018.10.1 2018.10.10 | |
| 452 | 896 | Monotonic Array | Java | Easy | 2018.9.1 | Array | 2018.10.11 2018.10.19 | |
| 453 | 897 | Incresing Order Search Tree | Java | Easy | 2018.9.1 | Tree | ||
| 454 | 898 | Bitwise ORs of Subarrays | Java | Medium | 2018.9.1 | Dynamic Programming | ||
| 455 | 227 | Basic Calculator II | Java | Medium | 2018.9.3 | String | 2018.10.27 | |
| 456 | 240 | Search a 2D Matrix II | Java | Medium | 2018.9.4 | Binary Search | 2018.11.7 | |
| 457 | 621 | Task Scheduler | Java | Medium | 2018.9.5 | Array, Greedy, Queue | 2018.10.15 2018.11.10 2019.1.7 | |
| 458 | 220 | Contains Duplicate III | Java | Medium | 2018.9.6 | Binary Search Tree | ||
| 459 | 900 | RLE Iterator | Java | Medium | 2018.9.13 | Array | ||
| 460 | 264 | Ugly Number II | Java | Medium | 2018.9.15 | Math, Dynamic Programming, Heap | ||
| 461 | 905 | Sort Array By Parity | Java | Easy | 2018.9.15 | Array | ||
| 462 | 904 | Fruit Into Baskets | Java | Medium | 2018.9.15 | Two Pointers | 2019.1.14 | |
| 463 | 907 | Sum of Subarray Minimums | Java | Medium | 2018.9.15 | Stack | ||
| 464 | 906 | Super Palindromes | Java | Hard | 2018.9.17 | Math | ||
| 465 | 698 | Partition to K Equal Sum Subsets | Java | Medium | 2018.9.21 | Recursion | ||
| 466 | 911 | Online Election | Java | Medium | 2018.9.23 | HashTable | 2019.3.6 | |
| 467 | 910 | Smallest Range II | Java | Medium | 2018.9.22 | Array | ||
| 468 | 909 | Snakes and Ladders | Java | Medium | 2018.9.22 | BFS | ||
| 469 | 908 | Smallest Range I | Java | Medium | 2018.9.22 | Array | ||
| 470 | 34 | Find First and Last Position of Element in Sorted Array | Java | Medium | 2018.9.22 | Binary Search | 2018.10.26 2018.11.12 | |
| 471 | 81 | Search in Rotated Sorted Array II | Java | Medium | 2018.10.2 | Binary Search | 2018.10.10 2018.10.26 2018.11.7 2019.2.21 | |
| 472 | 157 | Read N Characters Given Read4 | Java | Easy | 2018.10.4 | String | 2018.10.28 2018.11.12 2019.3.2 | |
| 473 | 260 | Single Number III | Java | Medium | 2018.10.4 | Bit Manipulation | 2018.10.30 | |
| 474 | 277 | Find the Celebrity | Java | Medium | 2018.10.4 | Array | 2018.10.27 2018.11.11 2019.2.27 | |
| 475 | 392 | Is Subsequence | Java | Medium | 2018.10.5 | Binary Search, Two Pointers | ||
| 476 | 721 | Accounts Merge | Java | Medium | 2018.10.6 | Union Find, DFS | 2018.10.25 2018.11.11 | |
| 477 | 74 | Search a 2D Matrix | Java | Medium | 2018.10.6 | Array | 2018.11.7 | |
| 478 | 917 | Reverse Only Letters | Java | Easy | 2018.10.6 | Two Pointer | ||
| 479 | 918 | Maxiumum Sum Circular Subarray | Java | Medium | 2018.10.6 | Array | ||
| 480 | 919 | Complete Binary Tree Inserter | Java | Medium | 2018.10.6 | Tree | ||
| 481 | 494 | Target Sum | Java | Medium | 2018.10.7 | Dynamic Programming, DFS | 2018.10.15 | |
| 482 | 523 | Continuous Subarray Sum | Java | Medium | 2018.10.7 | Dynamic Programming, HashMap | 2018.11.11 | |
| 483 | 360 | Sort Transformed Array | Java | Medium | 2018.10.7 | Two Pointers | ||
| 484 | 129 | Sum Root to Leaf Numbers | Java | Medium | 2018.10.7 | DFS | 2018.11.18 | |
| 485 | 498 | Diagonal Traverse | Java | Medium | 2018.10.8 | Array | 2018.10.22 | |
| 486 | 314 | Binary Tree Vertical Order Traversal | Java | Medium | 2018.10.8 | Tree, Hash Table | 2018.10.15 2018.10.23 2018.11.11 | |
| 487 | 785 | Is Graph Bipartite | Java | Medium | 2018.10.9 | Graph, DFS, BFS | 2018.10.27 2018.11.11 | |
| 488 | 678 | Valid Patrenthesis String | Java | Medium | 2018.10.9 | Greedy | ||
| 489 | 73 | Set Matrix Zeroes | Java | Medium | 2018.10.9 | Array | ||
| 490 | 398 | Random Pick Index | Java | Medium | 2018.10.10 | Reservoir Sampling | 2018.11.12 | |
| 491 | 209 | Minimum Size Subarray Sum | Java | Medium | 2018.10.10 | Array, Two Pointers, Binary Search | 2018.10.17 2018.10.23 2018.10.28 2018.11.15 | |
| 492 | 688 | Knight Probability in Chessboard | Java | Medium | 2018.10.10 | Dynamic Programming | 2019.2.26 2019.3.7 | |
| 493 | 524 | Longest Word in Dictionary through Deleting | Java | Medium | 2018.10.10 | Two Pointers, Sort | ||
| 494 | 304 | Range Sum Query 2D - Immutble | Java | Medium | 2018.10.10 | Dynamic Programming | ||
| 495 | 449 | Serialize and Deserialize BST | Java | Medium | 2018.10.11 | Tree | ||
| 496 | 426 | Convert Binary Search Tree to Sorted Doubly Linked List | Java | Medium | 2018.10.11 | Tree | 2018.10.23 2018.11.10 | |
| 497 | 251 | Flatten 2D Vector | Java | Medium | 2018.10.11 | Design | 2018.11.12 | |
| 498 | 395 | Longest Substring with At Least K Repeating Characters | Java | Medium | 2018.10.11 | Recursion | ||
| 499 | 416 | Partition Equal Subset Sum | Java | Medium | 2018.10.12 | Dynamic Programming | ||
| 500 | 90 | Subsets II | Java | Medium | 2018.10.13 | Backtracking | 2018.10.26 | |
| 501 | 430 | Flatten a Multilevel Doubly Linked List | Java | Medium | 2018.10.14 | LinkedList, DFS | 2018.10.27 | |
| 502 | 722 | Remove Comments | Java | Medium | 2018.10.14 | String | ||
| 503 | 662 | Maximum Width of Binary Tree | Java | Medium | 2018.10.15 | Tree | ||
| 504 | 230 | Kth Smallest Element in a BST | Java | Medium | 2018.10.18 | Tree, Binary Search | ||
| 505 | 925 | Long Pressed Name | Java | Easy | 2018.10.21 | String | ||
| 506 | 926 | Flip String to Monotone Increasing | Java | Medium | 2018.10.21 | String | ||
| 507 | 273 | Integer to English Words | Java | Hard | 2018.10.21 | String | 2018.11.17 | |
| 508 | 301 | Remove Invalid Parentheses | Java | Hard | 2018.10.22 | Backtracking | ||
| 509 | 65 | Valid Number | Java | Hard | 2018.10.22 | Math, String | 2018.10.25 | |
| 510 | 311 | Sparse Matrix Multiplication | Java | Medium | 2018.10.22 | Hash Table | ||
| 511 | 282 | Expression Add Operators | Java | Hard | 2018.10.22 | DFS, BackTracking | ||
| 512 | 99 | Recover Binary Search Tree | Java | Hard | 2018.10.24 | DFS, Tree | ||
| 513 | 428 | Serialize and Deserialize N-ary Tree | Java | Hard | 2018.10.24 | Tree | ||
| 514 | 305 | Number of Islands II | Java | Hard | 2018.10.26 | Union Find | ||
| 515 | 272 | Closest Binary Search Tree Value II | Java | Hard | 2018.10.26 | Stack, Tree | ||
| 516 | 128 | Longest Consecutive Sequence | Java | Hard | 2018.10.26 | Union Find, Array | ||
| 517 | 403 | Frog Jump | Java | Hard | 2018.10.26 | Dynamic Programming | ||
| 518 | 84 | Largest Rectangle in Histogram | Java | Hard | 2018.10.26 | Stack | 2019.2.17 | |
| 519 | 216 | Combination Sum III | Java | Medium | 2018.10.27 | Backtracking | 2019.2.5 2019.2.24 | |
| 520 | 377 | Combination Sum IV | Java | Medium | 2018.10.27 | Dynamic Programming | ||
| 521 | 269 | Alien Dictionary | Java | Hard | 2018.10.27 | Topological Sort | 2018.11.13 | |
| 522 | 791 | Custom Sort String | Java | Medium | 2018.10.27 2018.11.12 | Sort | ||
| 523 | 239 | Sliding Window Maximum | Java | Hard | 2018.10.27 | Queue | ||
| 524 | 29 | [Divide Two Integers][29] | Java | Medium | 2018.10.27 | Bit Manipulation | 2018.11.8 2018.11.11 | |
| 525 | 224 | Basic Calculator | Java | Hard | 2018.10.27 | Stack, Math | ||
| 526 | 295 | Find Median from Data Stream | Java | Hard | 2018.10.28 | Heap | 2019.4.21 | |
| 527 | 380 | Insert Delete GetRandom O(1) | Java | Medium | 2018.10.28 | Hash Map, Design | ||
| 528 | 381 | [Insert Delete GetRandom O(1) - - Duplicates Allowed][381] | Java | Hard | 2018.10.28 | Hash Map, LinkedHashSet, Design | 2018.11.5 | |
| 529 | 71 | Simplify Path | Java | Medium | 2018.10.28 | String, Stack | ||
| 530 | 286 | Walls and Gates | Java | Medium | 2018.10.28 | BFS | 2018.11.17 2019.2.27 | |
| 531 | 348 | [Design Tic-Tac-Toe][348] | Java | Medium | 2018.10.28 | Design | 2019.3.3 | |
| 532 | 708 | Insert into a Cyclic Sorted List | Java | Medium | 2018.10.28 | LinkedList | ||
| 533 | 261 | Graph Valid Tree | Java | Medium | 2018.10.30 | Union Find | 2019.3.1 | |
| 534 | 221 | Maximal Square | Java | Medium | 2018.11.3 | Stack, Dynamic Programming | 2018.11.8 2019.2.18 | |
| 535 | 154 | Find Minimum in Rotated Sorted Array II | Java | Hard | 2018.11.7 | Binary Search | ||
| 536 | 644 | Maximum Average Subarray II | Java | Hard | 2018.11.8 | Binary Search | ||
| 537 | 486 | Predict the Winner | Java | Medium | 2018.11.9 | Dynamic Programming, Minimax | ||
| 538 | 10 | Regular Expression Matching | Java | Hard | 2018.11.11 | Dynamic Programming, Backtracking | 2018.11.16 2019.3.8 | |
| 539 | 43 | Multiply Strings | Java | Medium | 2018,11,11 | String, Math | ||
| 540 | 382 | Linked List Random Node | Java | Medium | 2018.11.12 | Reservoir Sampling | ||
| 541 | 678 | Valid Parenthesis String | Java | Medium | 2018.11.12 | Stack | ||
| 542 | 247 | Strobogrammatic Number II | Java | Medium | 2018.11.12 | Recursion | 2018.11.17 | |
| 543 | 222 | Count Complete Tree Nodes | Java | Medium | 2018.11.14 | Tree | 2019.2.17 | |
| 544 | 307 | Range Sum Query - Mutable | Java | Medium | 2018.11.15 | Binary Indexed Tree | ||
| 545 | 689 | Maximum Sum of 3 Non-Overlapping Subarrays | Java | Hard | 2018.11.16 | Array, Dynamic Programming | ||
| 546 | 8 | String to Integer (atoi) | Java | Medium | 2018.11.16 | Math, String | ||
| 547 | 317 | Shortest Distance from All Buildings | Java | Hard | 2018.11.16 | BFS | ||
| 548 | 336 | Palindrome Pairs | Java | Hard | 2018.11.16 | Trie | ||
| 549 | 55 | Jump Game | Java | Medium | 2018.11.16 | Dynamic Programming, Greedy | 2019.1.16 | |
| 550 | 57 | Insert Interval | Java | Hard | 2018.11.16 | Array | ||
| 551 | 32 | Longest Valid Parentheses | Java | Hard | 2018.11.16 | Dynamic Programming | ||
| 552 | 567 | Permutation in String | Java | Medium | 2018.11.16 | Sliding Window | ||
| 553 | 117 | Populating Next Right Pointers in Each Node II | Java | Medium | 2018.11.16 | Tree | ||
| 554 | 636 | Exclusive Time of Functions | Java | Medium | 2018.11.16 | Stack | ||
| 555 | 44 | Wildcard Matching | Java | Hard | 2018.11.16 | Dynamic Programming | 2019.3.8 | |
| 556 | 452 | Minimum Number of Arrows to Burst Balloons | Java | Medium | 2018.11.17 | Greedy | ||
| 557 | 329 | Longest Increasing Path in a Matrix | Java | Hard | 2018.11.17 | DFS, Memorization | 2019.2.17 | |
| 558 | 291 | Word Pattern II | Java | Hard | 2018.11.17 | Backtracking | ||
| 559 | 140 | Word Break II | Java | Hard | 2018.11.17 | Dynamic Programming, Backtracking | ||
| 560 | 158 | Read N Characters Given Read4 II | Java | Hard | 2018.11.17 | String | 2019.2.17 2019.3.2 | |
| 561 | 862 | Shortest Subarray with Sum at Least K | Java | Hard | 2018.11.17 | Deque | ||
| 562 | 493 | Reverse Pairs | Java | Hard | 2018.11.17 | Divide and Conquer | ||
| 563 | 99 | |||||||
| 564 | 554 | Brick Wall | Java | Medium | 2018.11.17 | HashMap | ||
| 565 | 248 | Strobogrammatic Number III | Java | Hard | 2018.11.17 | Recuision | ||
| 566 | 622 | Design Circular Queue | Java | Medium | 2018.11.17 | Design | ||
| 567 | 332 | Reconstruct Itinerary | Java | Medium | 2018.11.17 | HashMap, DFS | ||
| 568 | 921 | Minimum Add to Make Parentheses Valid | Java | Medium | 2018.11.26 | Stack, Greedy | ||
| 569 | 933 | Number of Recent Calls | Java | Easy | 2018.11.26 | Queue | ||
| 570 | 929 | Unique Email Addresses | Java | Easy | 2018.11.26 | String | 2019.1.14 | |
| 571 | 930 | Binary Subarrays With Sum | Java | Medium | 2018.11.26 | Hash Table, Two Pointers | ||
| 572 | 815 | Bus Routes | Java | Hard | 2018.11.30 | BFS | ||
| 573 | 390 | Elimination Game | Java | Medium | 2018.12.1 | Math | ||
| 574 | 949 | Largest Time for Given Digits | Java | Easy | 2018.12.1 | Math, DFS | ||
| 575 | 950 | Reveal Cards in Increasing Order | Java | Medium | 2018.12.1 | Array, Deque | ||
| 576 | 951 | Flip Equivalent Binary Trees | Java | Medium | 2018.12.1 | Tree | 2019.2.27 | |
| 577 | 953 | Verifying an Alien Dictionary | Java | Easy | 2018.12.16 | Hash Table | ||
| 578 | 954 | Array of Doubled Pairs | Java | Medium | 2018.12.17 | Hash Table | ||
| 579 | 955 | Delete Columns to Make Sorted II | Java | Medium | 2018.12.18 | Greedy | ||
| 580 | 957 | Prison Cells After N Days | Java | Medium | 2018.12.19 | Hash Table | ||
| 581 | 959 | Regions Cut By Slashes | Java | Medium | 2018.12.21 | Union Find | ||
| 582 | 958 | Check Completeness of a Binary Tree | Java | Medium | 2018.12.22 | Tree | ||
| 583 | 965 | Univalued Binary Tree | Java | Easy | 2019.1.5 | Tree | ||
| 584 | 966 | Vowel Spellchecker | Java | Medium | 2019.1.6 | Hash Table, String | ||
| 585 | 970 | Powerful Integers | Java | Easy | 2019.1.7 | Math | ||
| 586 | 967 | Numbers with same consecutive differences | Java | Medium | 2019.1.8 | Dynamic Programming | ||
| 587 | 968 | Pancake Sorting | Java | Medium | 2019.1.8 | Array, Sort | ||
| 588 | 971 | Flip Binary Tree to Match Preorder Traversal | Java | Medium | 2019.1.8 | DFS | ||
| 589 | 402 | Remove K Digits | Java | Medium | 2019.1.9 | Stack, Greedy | 2019.2.10 | |
| 590 | 223 | Rectangle Area | Java | Medium | 2019.1.9 | Math | ||
| 591 | 309 | Best Time To Buy and Sell Stock with Cooldown | Java | Medium | 2019.1.9 | Dynamic Programming | ||
| 592 | 713 | Subarray Product Less Than K | Java | Medium | 2019.1.10 | Two Pointers | ||
| 593 | 931 | Minimum Falling Path Sum | Java | Medium | 2019.1.11 | Dynamic Programming | ||
| 594 | 932 | Beautiful Array | Java | Medium | 2019.1.11 | Divide and Conquer | ||
| 595 | 819 | Most Common Word | Java | Easy | 2019.1.12 | String | ||
| 596 | 683 | K Empty Slots | Java | Hard | 2019.1.16 | HashTable | ||
| 597 | 743 | Network Delay Time | Java | Easy | 2019.1.17 | Graph | 2019.2.28 | |
| 598 | 787 | Cheapest Flight Within K Stops | Java | Medium | 2019.1.18 | Graph | ||
| 599 | 131 | Palindrome Partitioning | Java | Medium | 2019.1.18 | Backtracking | ||
| 600 | 279 | Perfect Square | Java | Medium | 2019.1.18 | Dynamic Programming | ||
| 601 | 384 | Shuffle an Array | Java | Medium | 2019.1.18 | Design | ||
| 602 | 977 | Squares of a Sorted Array | Java | Easy | 2019.1.20 | Two Pointers, Sort | 2019.3.1 | |
| 603 | 978 | Longest Turbulent Subarray | Java | Medium | 2019.1.26 | Two Pointers | ||
| 604 | 265 | Paint House II | Java | Hard | 2019.1.27 | Dynamic Programming | ||
| 605 | 188 | Best Time to Buy and Sell Stock IV | Java | Hard | 2019.1.28 | Dynamic Programming | ||
| 606 | 982 | Triples with Bitwise AND Equal To Zero | Java | Hard | 2019.1.28 | Dynamic Programming | ||
| 607 | 979 | Distribute Coins in Binary Tree | Java | Medium | 2019.1.28 | DFS | ||
| 608 | 984 | String Without AAA or BBB | Java | Easy | 2019.2.2 | Greedy | ||
| 609 | 985 | Sum of Even Numbers After Queries | Java | Easy | 2019.2.3 | Array | ||
| 610 | 835 | Image Overlap | Java | Medium | 2019.2.5 | Array | ||
| 611 | 132 | Palindrome Partitioning II | Java | Hard | 2019.2.5 | Dynamic Programming | ||
| 612 | 399 | Evaluate Division | Java | Medium | 2019.2.6 | Union Find, BFS | ||
| 613 | 299 | Bulls and Cows | Java | Medium | 2019.2.6 | Hash Table | 2019.2.12 2019.3.2 | |
| 614 | 87 | Scramble String | Java | Hard | 2019.2.9 | Dynamic Programming | ||
| 615 | 312 | Burst Balloons | Java | Hard | 2019.2.9 | Dynamic Programming | ||
| 616 | 980 | Unique Paths III | Java | Hard | 2019.2.10 | Backtracking | ||
| 617 | 228 | Summary Ranges | Java | Medium | 2019.2.10 | Two Pointers | ||
| 618 | 701 | Insert Into a Binary Search Tree | Java | Medium | 2019.2.11 | Tree | ||
| 619 | 723 | Candy Crush | Java | Medium | 2019.2.11 | Two Pointers | ||
| 620 | 702 | Search in a Sorted Array of Unknown Size | Java | Medium | 2019.2.11 | Binary Search | ||
| 621 | 776 | Split BST | Java | Medium | 2019.2.11 | BST | ||
| 622 | 684 | Redundant Connection | Java | Medium | 2019.2.11 | Union Find | ||
| 623 | 320 | Generalized Abbreviation | Java | Medium | 2019.2.11 | Backtracking | ||
| 624 | 249 | Group Shifted Strings | Java | Medium | 2019.2.11 | HashTable | ||
| 625 | 386 | Lexicographical Numbers | Java | Medium | 2019.2.11 | DFS | ||
| 626 | 549 | Binary Tree Longest Consecutive Sequence II | Java | Medium | 2019.2.11 | Tree | ||
| 627 | 424 | Longest Repeating Character Replacement | Java | Medium | 2019.2.11 | Two Pointers, Sliding Window | 2019.2.25 | |
| 628 | 135 | Candy | Java | Hard | 2019.2.12 | Greedy | 2019.2.17 2019.2.27 | |
| 629 | 591 | Tag Validator | Java | Hard | 2019.2.12 | Stack | ||
| 630 | 562 | Longest Line of Consecutive One in Matrix | Java | Medium | 2019.2.13 | Dynamic Programming | ||
| 631 | 737 | Sentence Similarity II | Java | Medium | 2019.2.13 | Union Find | ||
| 632 | 640 | Solve the Equation | Java | Medium | 2019.2.13 | Math, Stack | ||
| 633 | 659 | Split Array into Consecutive Subsequences | Java | Medium | 2019.2.13 | Heap, Greedy | ||
| 634 | 334 | Increasing Triplet Subsequence | Java | Medium | 2019.2.13 | Array | ||
| 635 | 450 | Delete Node in a BST | Java | Medium | 2019.2.13 | Tree | ||
| 636 | 284 | Peeking Iterator | Java | Medium | 2019.2.13 | Design | ||
| 637 | 616 | Add Bold Tag in String | Java | Medium | 2019.2.13 | String | ||
| 638 | 388 | Longest Absolute File Path | Java | Medium | 2019.2.14 | String | ||
| 639 | 935 | Knight Dialer | Java | Medium | 2019.2.14 | Dynamic Programming | ||
| 640 | 433 | Minimum Genetic Mutation | Java | Medium | 2019.2.14 | BFS | ||
| 641 | 375 | Guess Number Higher or Lower II | Java | Medium | 2019.2.14 | Dynamic Programming | 2019.2.25 | |
| 642 | 417 | Pacific Atlantic Water Flow | Java | Medium | 2019.2.14 | BFS, DFS | ||
| 643 | 115 | Distinct Subsequences | Java | Medium | 2019.2.14 | Dynamic Programming | ||
| 644 | 288 | Unique Word Abbreviation | Java | Medium | 2019.2.15 | Hash Table | ||
| 645 | 457 | Circular Array Loop | Java | Medium | 2019.2.15 | Two Pointers | ||
| 646 | 777 | [Swap Adjacent in LR String][777] | Java | Medium | 2019.2.15 | Two Pointers | 2019.2.18 | |
| 647 | 418 | Sentence Screen Fitting | Java | Medium | 2019.2.15 | Two Pointers | ||
| 648 | 333 | Largest BST Subtree | Java | Medium | 2019.2.15 | Tree | ||
| 649 | 187 | Repeated DNA Sequences | Java | Medium | 2019.2.15 | HashTable | 2019.2.26 | |
| 650 | 753 | Cracking the Safe | Java | Hard | 2019.2.16 | DFS | 2019.2.18 | |
| 651 | 857 | Minimum Cost to Hire K Workers | Java | Hard | 2019.2.16 | Heap | ||
| 652 | 639 | Decode Ways II | Java | Hard | 2019.2.17 | Dynamic Programming | ||
| 653 | 843 | Guess the word | Java | Hard | 2019.2.17 | Minimax | ||
| 654 | 774 | Minimize Max Distance to Gas Station | Java | Hard | 2019.2.17 | Dynamic Programming, Heap, Binary Search | ||
| 655 | 818 | Race Car | Java | Hard | 2019.2.17 | BFS, Dynamic Programming | ||
| 656 | 489 | Robot Room Cleaner | Java | Hard | 2019.2.18 | DFS | ||
| 657 | 939 | Minimum Area Rectangle | Java | Medium | 2019.2.18 | HashTable | ||
| 658 | 833 | Find And Replace in String | Java | Medium | 2019.2.18 | HashTable | ||
| 659 | 410 | [Split Array Largest Sum][410] | Java | Hard | 2019.2.18 | Dynamic Programming | 2019.2.26 | |
| 660 | 694 | Number of Distinct Islands | Java | Medium | 2019.2.18 | DFS | ||
| 661 | 85 | Maximal Rectangle | Java | Hard | 2019.2.18 | Stack | ||
| 662 | 212 | Word Search II | Java | Hard | 2019.2.20 | Trie, DFS | ||
| 663 | 60 | Permutation Sequence | Java | Medium | 2019.2.20 | Math | ||
| 664 | 37 | Sudoku Solver | Java | Hard | 2019.2.21 | Backtracking | ||
| 665 | 41 | First Missing Positive | Java | Hard | 2019.2.21 | Array | 2019.3.6 | |
| 666 | 527 | Word Abbreviation | Java | Hard | 2019.2.22 | Trie, HashTable | ||
| 667 | 77 | Combinations | Java | Medium | 2019.2.22 | Backtracking | ||
| 668 | 316 | Remove Duplicate Letters | Java | Hard | 2019.2.23 | Stack | ||
| 669 | 548 | Split Array With Equal Sum | Java | Medium | 2019.2.25 | Array | ||
| 670 | 834 | Sum of Distances in Tree | Java | Hard | 2019.2.25 | Tree, DFS | ||
| 671 | 997 | Find the Town Judge | Java | Easy | 2019.2.27 | Graph | ||
| 672 | 685 | Redundant Connection II | Java | Hard | 2019.3.1 | Graph | ||
| 673 | 803 | Bricks Falling When Hit | Java | Hard | 2019.3.1 | Union Find | ||
| 674 | 837 | New 21 Game | Java | Medium | 2019.3.1 | Dynamic Programming | ||
| 675 | 593 | Valid Square | Java | Medium | 2019.3.2 | Math | ||
| 676 | 150 | Evaluate Reverse Polish Notation | Java | Medium | 2019.3.3 | Stack | ||
| 677 | 794 | Valid Tic-Tac-Toe State | Java | Medium | 2019.3.3 | Array | ||
| 678 | 1000 | Minimum Cost to Merge Stones | Java | Hard | 2019.3.3 | Dynamic Programming | ||
| 679 | 1004 | Max Consecutive Ones III | Java | Medium | 2019.3.3 | Sliding Window, Two Pointers | ||
| 680 | 487 | Max Consecutive Ones II | Java | Medium | 2019.3.3 | Sliding Window, Two Pointers | ||
| 681 | 797 | All Paths From Source to Target | Java | Medium | 2019.3.5 | Graph | ||
| 682 | 632 | Smallest Range | Java | Hard | 2019.3.5 | Heap | ||
| 683 | 947 | Most Stones Removed with Same Row or Column | Java | Medium | 2019.3.6 | Union Find | ||
| 684 | 765 | Couples Holding Hands | Java | Hard | 2019.3.6 | Union Find | ||
| 685 | 854 | K-Similar Strings | Java | Hard | 2019.3.6 | BFS, Backtracking | ||
| 686 | 509 | Finbonacci Number | Java | Easy | 2019.3.12 | Dynamic Programming | ||
| 687 | 310 | Minimum Height Trees | Java | Medium | 2019.3.13 | BFS, Graph | ||
| 688 | 547 | Friend Circles | Java | Medium | 2019.3.13 | Union Find | ||
| 689 | 611 | Valid Triangle Number | Java | Medium | 2019.3.13 | Array | ||
| 690 | 475 | Heaters | Java | Easy | 2019.3.13 | Binary Search | ||
| 691 | 706 | Design HashMap | Java | Easy | 2019.3.13 | Design | ||
| 692 | 705 | Design HashSet | Java | Easy | 2019.3.13 | Design | ||
| 693 | 707 | Design Linked List | Java | Easy | 2019.3.15 | Design | ||
| 694 | 655 | Print Binary Tree | Java | Medium | 2019.3.15 | Tree | ||
| 695 | 362 | Design Hit Counter | Java | Medium | 2019.3.15 | Design | ||
| 696 | 788 | Rotated Digits | Java | Easy | 2019.3.19 | Dynamic Programming | ||
| 697 | 289 | Game of Life | Java | Medium | 2019.3.20 | Array | ||
| 698 | 93 | Restore IP Addresses | Java | Medium | 2019.3.22 | Backtracking | ||
| 699 | 89 | Gray Code | Java | Medium | 2019.3.23 | Backtracking | ||
| 700 | 156 | Binary Tree Upside Down | Java | Medium | 2019.3.23 | Tree | ||
| 701 | 274 | H-Index | Java | Medium | 2019.3.24 | Sort, HashTable, Binary Search | ||
| 702 | 275 | H-Index II | Java | Medium | 2019.3.25 | Binary Search | ||
| 703 | 539 | Minimum Time Difference | Java | Medium | 2019.3.25 | Sort | ||
| 704 | 130 | Surrounded Regions | Java | Medium | 2019.3.26 | Union Find | ||
| 705 | 163 | Missing Ranges | Java | Medium | 2019.3.26 | Array | ||
| 706 | 166 | Fraction to Recurring Decimal | Java | Medium | 2019.3.27 | Hash Table | ||
| 707 | 201 | Bitwise AND of Numbers Range | Java | Medium | 2019.3.28 | Bit Manipulation | ||
| 708 | 536 | Construct Binary Tree from String | Java | Medium | 2019.3.28 | Tree | ||
| 709 | 319 | Bulb Switcher | Java | Medium | 2019.3.30 | Math | ||
| 710 | 718 | Maximum Length of Repeated Subarray | Java | Medium | 2019.3.31 | Dynamic Programming | ||
| 711 | 542 | 01 Matrix | Java | Medium | 2019.4.1 | BFS | ||
| 712 | 670 | Maximum Swap | Java | Medium | 2019.4.2 | Array | ||
| 713 | 646 | Maximum Length of Pair Chain | Java | Medium | 2019.4.3 | Dynamic Programming, Greedy | ||
| 714 | 1017 | Convert to Base -2 | Java | Medium | 2019.4.4 | Math | ||
| 715 | 1018 | Binary Prefix Divisible By 5 | Java | Easy | 2019.4.4 | Array | ||
| 716 | 1019 | Next Greater Node In Linked List | Java | Medium | 2019.4.4 | Stack | ||
| 717 | 1020 | Number of Enclaves | Java | Medium | 2019.4.4 | Union Find | ||
| 718 | 510 | Inorder Successor in BST II | Java | Medium | 2019.4.8 | Tree | ||
| 719 | 365 | Water and Jug Problem | Java | Medium | 2019.4.9 | Math | ||
| 720 | 368 | Largest Divisible Subset | Java | Medium | 2019.4.9 | Dynamic Programming | ||
| 721 | 343 | Integer Break | Java | Medium | 2019.4.9 | Dynamic Programming | ||
| 722 | 373 | Find K Pairs with Smallest Sums | Java | Medium | 2019.4.10 | Heap | ||
| 723 | 480 | Sliding Window Median | Java | Hard | 2019.4.13 | Heap | ||
| 724 | 652 | Find Duplicate Subtrees | Java | Medium | 2019.4.13 | HashTable | ||
| 725 | 1022 | Sum of Root To Leaf Binary Numbers | Java | Easy | 2019.4.14 | DFS | ||
| 726 | 164 | Maximum Gap | Java | Hard | 2019.4.15 | Bucket Sort | ||
| 727 | 460 | LFU Cache | Java | Hard | 2019.4.17 | HashTable, Design | ||
| 728 | 529 | Minuesweeper | Java | Medium | 2019.4.17 | BFS | ||
| 729 | 934 | Shortest Bridge | Java | Medium | 2019.4.17 | DFS, BFS | ||
| 730 | 895 | Maximum Frequency Stack | Java | Hard | 2019.4.21 | Stack | ||
| 731 | 45 | Jump Game II | Java | Hard | 2019.5.5 | Greedy | ||
| 732 | 924 | Minimize Malware Spread | Java | Hard | 2019.5.7 | Union Find | ||
| 733 | 609 | Find Duplicate File in System | Java | Medium | 2019.5.9 | HashMap | ||
| 734 | 1029 | Two City Scheduling | Java | Easy | 2019.5.14 | Greedy | ||
| 735 | 1030 | Matrix Cells in Distance Order | Java | Easy | 2019.5.14 | BFS | ||
| 736 | 1031 | Maximum Sum of Two Non-Overlapping Subarrays | Java | Medium | 2019.5.17 | Dynamic Programming | ||
| 737 | 1033 | Moving Stones Until Consecutive | Java | Easy | 2019.5.28 | Array | ||
| 738 | 1078 | Occurences After Bigram | Java | Easy | 2019.6.12 | String | ||
| 739 | 1079 | Letter Tile Possiblities | Java | Medium | 2019.6.13 | Backtracking | ||
| 740 | 1080 | Insufficient Nodes in Root to Leaf Paths | Java | Medium | 2019.6.13 | DFS | ||
| 741 | 1081 | Smallest Subsequence of Distinct Characters | Java | Medium | 2019.6.13 | Stack | ||
| 742 | 1085 | Sum of Digits in the Minimum Number | Java | Easy | 2019.6.15 | Array | ||
| 743 | 1086 | High Five | Java | Easy | 2019.6.15 | Hash Table | ||
| 744 | 1087 | Brace Expansion | Java | Medium | 2019.6.16 | BFS, Backtracking | ||
| 745 | 1089 | Duplicate Zeros | Java | Easy | 2019.6.17 | Array | ||
| 746 | 1071 | Greatest Common Divisor of Strings | Java | Easy | 2019.6.18 | String | ||
| 747 | 1064 | Fixed Point | Java | Easy | 2019.6.20 | Binary Search | ||
| 748 | 1090 | Largest Values From Labels | Java | Medium | 2019.7.12 | Greedy, HashTable | ||
| 749 | 1099 | Two Sum Less Than K | Java | Easy | 2019.7.12 | Array | ||
| 750 | 1119 | Remove Vowels from A String | Java | Easy | 2019.7.26 | String | ||
| 751 | 1134 | Armstrong Number | Java | Easy | 2019.7.29 | Math | ||
| 752 | 1133 | Largest Number | Java | Easy | 2019.7.29 | Hash Table | ||
| 753 | 1135 | Connecting Cities with Minimum Cost | Java | Medium | 2019.7.30 | Graph | ||
| 754 | 1114 | Print in Order | Java | Easy | 2019.8.2 | Thread | ||
| 755 | 1143 | Longest Common Subsequence | Java | Medium | 2019.8.2 | Dynamic Programming | ||
| 756 | 1137 | N-th Tribonacci Number | Java | Easy | 2019.8.3 | Recursion | ||
| 757 | 1138 | Alphabet Board Path | Java | Medium | 2019.8.3 | HashTable | ||
| 758 | 1155 | Number of Dice Rolls with Target Sum | Java | Medium | 2019.8.13 | Dynamic Programming | ||
| 759 | 1154 | Day of the Year | Java | Easy | 2019.8.14 | String | ||
| 760 | 1156 | Swap for Longest Repeated Character Substring | Java | Medium | 2019.8.14 | Two Pointers | ||
| 761 | 1150 | Check if a number is Majority Element in a Sorted Array | Java | Easy | 2019.8.14 | Binary Search | ||
| 762 | 1175 | Prime Arrangements | Java | Easy | 2019.9.6 | Math | ||
| 763 | 1176 | Diet Plan Performance | Java | Easy | 2019.9.6 | Two Pointers | ||
| 764 | 1177 | Can Make Palindrome from Substring | Java | Medium | 2019.9.6 | String | ||
| 765 | 1171 | Remove Zero Sum Consecutive Nodes from Linked List | Java | Medium | 2019.9.17 | Linked List | ||
| 766 | 1170 | Compare Strings by Frequency of the Smallest Character | Java | Easy | 2019.9.17 | String | ||
| 767 | 1169 | Invalid Transactions | Java | Medium | 2019.9.18 | HashTable | ||
| 768 | 1167 | Minimum Cost to Connect Sticks | Java | Medium | 2019.9.18 | Greedy | ||
| 769 | 1165 | Single-Row Keyboard | Java | Easy | 2019.9.18 | String | ||
| 770 | 1162 | As Far from Land as Possible | Java | Medium | 2019.9.20 | BFS | ||
| 771 | 1180 | Count Substrings with Only One Distinct Letter | Java | Easy | 2019.10.6 | Two Pointers | ||
| 772 | 1181 | Before and After Puzzle | Java | Medium | 2019.10.7 | HashMap | ||
| 773 | 1182 | Shortest Distance to Target Color | Java | Medium | 2019.10.8 | Binary Search | ||
| 774 | 1184 | Distance Between Bus Stops | Java | Easy | 2019.10.9 | Array | ||
| 775 | 1185 | Day of the Week | Java | Easy | 2019.10.12 | Array | ||
| 776 | 1189 | Maximum Number of Balloons | Java | Easy | 2019.10.13 | Array | ||
| 777 | 1221 | Split a String in Balanced Strings | Java | Easy | 2019.10.16 | Greedy | ||
| 778 | 1219 | Path with Maximum Gold | Java | Medium | 2019.10.17 | Backtracking | ||
| 779 | 1243 | Array Transformation | Java | Easy | 2019.11.2 | Array | ||
| 780 | 1258 | Synonymous Sentences | Java | Medium | 2019.11.16 | UnionFind, HashMap | ||
| 781 | 1260 | Shift 2D Grid | Java | Easy | 2019.11.17 | Array | ||
| 782 | 1261 | Find Elements in a Contaminated Binary Tree | Java | Medium | 2019.11.20 | DFS | ||
| 783 | 1265 | Print Immutable Linked List in Reverse | Java | Medium | 2019.11.24 | LinkedList | ||
| 784 | 1266 | Minimum Time Visiting All Points | Java | Easy | 2019.11.30 | Array | ||
| 785 | 1267 | Count Servers that Communicate | Java | Medium | 2019.12.1 | Graph | ||
| 786 | 1268 | Search Suggestions System | Java | Medium | 2019.12.1 | String | ||
| 787 | 1271 | Hexspeak | Java | Easy | 2019.12.8 | String | ||
| 788 | 1272 | Remove Interval | Java | Medium | 2019.12.14 | Array | ||
| 789 | 1342 | Number of Steps to Reduce a Number to Zero | Java | Easy | 2020.2.10 | Bit Manipulation | ||
| 790 | 1347 | Minimum Number of Steps to Make Two Strings Anagram | Java | Medium | 2020.2.11 | String | ||
| 791 | 1346 | Check If N and Its Double Exist | Java | Easy | 2020.2.12 | Array | ||
| 792 | 1374 | Generate a String With Characters That Have Odd Counts | Java | Easy | 2020.3.8 | String | ||
| 793 | 1380 | Lucky Numbers in a Matrix | Java | Easy | 2020.3.15 | Array | ||
| 794 | 1381 | Design a Stack With Increment Operation | Java | Medium | 2020.3.15 | Stack | ||
| 795 | 1382 | Balance a Binary Search Tree | Java | Medium | 2020.3.16 | Tree |
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