Leetcode-Premium id title Difficulty Python 1 156. Binary Tree Upside Down Middle Solution 2 157. Read N Characters Given Read4 Easy Solution 3 158. Read N Characters Given Read4 II - Call multiple times Difficult Solution 4 159. Longest Substring with At Most Two Distinct Characters Difficult Solution 5 161. One Edit Distance Middle Solution 6 163. Missing Ranges Middle Solution 7 170. Two Sum III - Data structure design Easy Solution 8 186. Reverse Words in a String II Middle Solution 9 243. Shortest Word Distance Easy Solution 10 244. Shortest Word Distance II Middle Solution 11 245. Shortest Word Distance III Middle Solution 12 246. Strobogrammatic Number Easy Solution 13 247. Strobogrammatic Number II Middle Solution 14 248. Strobogrammatic Number III Difficult Solution 15 249. Group Shifted Strings Middle Solution 16 250. Count Univalue Subtrees Middle Solution 17 251. Flatten 2D Vector Middle Solution 18 252. Meeting Rooms Easy Solution 19 253. Meeting Rooms II Middle Solution 20 254. Factor Combinations Middle Solution 21 255. Verify Preorder Sequence in Binary Search Tree Middle Solution 22 256. Paint House Easy Solution 23 259. 3Sum Smaller Middle Solution 24 261. Graph Valid Tree Middle Solution 25 265. Paint House II Difficult Solution 26 266. Palindrome Permutation Easy Solution 27 267. Palindrome Permutation II Middle Solution 28 269. Alien Dictionary Difficult Solution 29 270. Closest Binary Search Tree Value Easy Solution 30 271. Encode and Decode Strings Middle Solution 31 272. Closest Binary Search Tree Value II Difficult Solution 32 276. Paint Fence Easy Solution 33 277. Find the Celebrity Middle Solution 34 280. Wiggle Sort Middle Solution 35 281. Zigzag Iterator Middle Solution 36 285. Inorder Successor in BST Middle Solution 37 286. Walls and Gates Middle Solution 38 288. Unique Word Abbreviation Middle Solution 39 291. Word Pattern II Difficult Solution 40 293. Flip Game Easy Solution 41 294. Flip Game II Middle Solution 42 296. Best Meeting Point Difficult Solution 43 298. Binary Tree Longest Consecutive Sequence Middle Solution 44 302. Smallest Rectangle Enclosing Black Pixels Difficult Solution 45 305. Number of Islands II Difficult Solution 46 308. Range Sum Query 2D - Mutable Difficult Solution 47 311. Sparse Matrix Multiplication Middle Solution 48 314. Binary Tree Vertical Order Traversal Middle Solution 49 317. Shortest Distance from All Buildings Difficult Solution 50 320. Generalized Abbreviation Middle Solution 51 323. Number of Connected Components in an Undirected Graph Middle Solution 52 325. Maximum Size Subarray Sum Equals k Middle Solution 53 333. Largest BST Subtree Middle Solution 54 339. Nested List Weight Sum Easy Solution 55 340. Longest Substring with At Most K Distinct Characters Difficult Solution 56 346. Moving Average from Data Stream Easy Solution 57 348. Design Tic-Tac-Toe Middle Solution 58 351. Android Unlock Patterns Middle Solution 59 353. Design Snake Game Middle Solution 60 356. Line Reflection Middle Solution 61 358. Rearrange String k Distance Apart Difficult Solution 62 359. Logger Rate Limiter Easy Solution 63 360. Sort Transformed Array Middle Solution 64 361. Bomb Enemy Middle Solution 65 362. Design Hit Counter Middle Solution 66 364. Nested List Weight Sum II Middle Solution 67 366. Find Leaves of Binary Tree Middle Solution 68 369. Plus One Linked List Middle Solution 69 370. Range Addition Middle Solution 70 379. Design Phone Directory Middle Solution 71 408. Valid Word Abbreviation Easy Solution 72 411. Minimum Unique Word Abbreviation Difficult Solution 73 418. Sentence Screen Fitting Middle Solution 74 422. Valid Word Square Easy Solution 75 425. Word Squares Difficult Solution 76 439. Ternary Expression Parser Middle Solution 77 444. Sequence Reconstruction Middle Solution 78 465. Optimal Account Balancing Difficult Solution 79 469. Convex Polygon Middle Solution 80 471. Encode String with Shortest Length Difficult Solution 81 484. Find Permutation Middle Solution 82 487. Max Consecutive Ones II Middle Solution 83 490. The Maze Middle Solution 84 499. The Maze III Difficult Solution 85 505. The Maze II Middle Solution 86 527. Word Abbreviation Difficult Solution 87 531. Lonely Pixel I Middle Solution 88 533. Lonely Pixel II Middle Solution 89 536. Construct Binary Tree from String Middle Solution 90 544. Output Contest Matches Middle Solution 91 545. Boundary of Binary Tree Middle Solution 92 548. Split Array with Equal Sum Middle Solution 93 549. Binary Tree Longest Consecutive Sequence II Middle Solution 94 555. Split Concatenated Strings Middle Solution 95 562. Longest Line of Consecutive One in Matrix Middle Solution 96 568. Maximum Vacation Days Difficult Solution 97 569. Median Employee Salary Difficult Solution 98 570. Managers with at Least 5 Direct Reports Middle Solution 99 571. Find Median Given Frequency of Numbers Difficult Solution 100 573. Squirrel Simulation Middle Solution 101 574. Winning Candidate Middle Solution 102 577. Employee Bonus Easy Solution 103 578. Get Highest Answer Rate Question Middle Solution 104 579. Find Cumulative Salary of an Employee Difficult Solution 105 580. Count Student Number in Departments Middle Solution 106 582. Kill Process Middle Solution 107 584. Find Customer Referee Easy Solution 108 585. Investments in 2016 Middle Solution 109 586. Customer Placing the Largest Number of Orders Easy Solution 110 588. Design In-Memory File System Difficult Solution 111 597. Friend Requests I: Overall Acceptance Rate Easy Solution 112 602. Friend Requests II: Who Has the Most Friends Middle Solution 113 603. Consecutive Available Seats Easy Solution 114 604. Design Compressed String Iterator Easy Solution 115 607. Sales Person Easy Solution 116 608. Tree Node Middle Solution 117 610. Triangle Judgement Easy Solution 118 612. Shortest Distance in a Plane Middle Solution 119 613. Shortest Distance in a Line Easy Solution 120 614. Second Degree Follower Middle Solution 121 615. Average Salary: Departments VS Company Difficult Solution 122 616. Add Bold Tag in String Middle Solution 123 618. Students Report By Geography Difficult Solution 124 619. Biggest Single Number Easy Solution 125 624. Maximum Distance in Arrays Easy Solution 126 625. Minimum Factorization Middle Solution 127 631. Design Excel Sum Formula Difficult Solution 128 634. Find the Derangement of An Array Middle Solution 129 635. Design Log Storage System Middle Solution 130 642. Design Search Autocomplete System Difficult Solution 131 644. Maximum Average Subarray II Difficult Solution 132 651. 4 Keys Keyboard Middle Solution 133 656. Coin Path Difficult Solution 134 660. Remove 9 Difficult Solution 135 663. Equal Tree Partition Middle Solution 136 666. Path Sum IV Middle Solution 137 681. Next Closest Time Middle Solution 138 683. K Empty Slots Difficult Solution 139 694. Number of Distinct Islands Middle Solution 140 711. Number of Distinct Islands II Difficult Solution 141 716. Max Stack Easy Solution 142 723. Candy Crush Middle Solution 143 727. Minimum Window Subsequence Difficult Solution 144 734. Sentence Similarity Easy Solution 145 737. Sentence Similarity II Middle Solution 146 743. Closest Leaf in a Binary Tree Middle Solution 147 751. Number Of Corner Rectangles Middle Solution 148 752. IP to CIDR Easy Solution 149 756. Pour Water Middle Solution 150 758. Convert Binary Search Tree to Sorted Doubly Linked List Middle Solution 151 760. Bold Words in String Easy Solution 152 761. Employee Free Time Difficult Solution 153 762. Find Anagram Mappings Easy Solution 154 765. Serialize and Deserialize N-ary Tree Difficult Solution 155 771. Encode N-ary Tree to Binary Tree Difficult Solution 156 785. Basic Calculator III Difficult Solution 157 786. Search in a Sorted Array of Unknown Size Middle Solution 158 788. Minimize Max Distance to Gas Station Difficult Solution 159 791. Split BST Middle Solution 160 818. Similar RGB Color Easy Solution 161 850. Insert into a Cyclic Sorted List Middle Solution 162 865. Robot Room Cleaner Difficult Solution