| 1143 | Longest Common Subsequence | Medium | Top_100_Liked_Questions, String, Dynamic_Programming, Algorithm_II_Day_17_Dynamic_Programming, Dynamic_Programming_I_Day_19, Udemy_Dynamic_Programming | 307 | 38.36 |
| 0994 | Rotting Oranges | Medium | Array, Breadth_First_Search, Matrix, Algorithm_I_Day_9_Breadth_First_Search_Depth_First_Search, Level_2_Day_10_Graph/BFS/DFS | 308 | 57.93 |
| 0864 | Shortest Path to Get All Keys | Hard | Breadth_First_Search, Bit_Manipulation | 176 | 100.00 |
| 0763 | Partition Labels | Medium | Top_100_Liked_Questions, String, Hash_Table, Greedy, Two_Pointers, Data_Structure_II_Day_7_String | 235 | 84.75 |
| 0739 | Daily Temperatures | Medium | Top_100_Liked_Questions, Array, Stack, Monotonic_Stack, Programming_Skills_II_Day_6 | 936 | 80.54 |
| 0725 | Split Linked List in Parts | Medium | Linked_List | 162 | 95.00 |
| 0724 | Find Pivot Index | Easy | Array, Prefix_Sum, Level_1_Day_1_Prefix_Sum | 255 | 88.92 |
| 0722 | Remove Comments | Medium | Array, String | 164 | 100.00 |
| 0721 | Accounts Merge | Medium | Array, String, Depth_First_Search, Breadth_First_Search, Union_Find | 364 | 100.00 |
| 0720 | Longest Word in Dictionary | Medium | Array, String, Hash_Table, Sorting, Trie | 209 | 100.00 |
| 0719 | Find K-th Smallest Pair Distance | Hard | Array, Sorting, Binary_Search, Two_Pointers | 172 | 100.00 |
| 0718 | Maximum Length of Repeated Subarray | Medium | Array, Dynamic_Programming, Binary_Search, Sliding_Window, Hash_Function, Rolling_Hash | 270 | 91.43 |
| 0717 | 1-bit and 2-bit Characters | Easy | Array | 165 | 100.00 |
| 0715 | Range Module | Hard | Design, Ordered_Set, Segment_Tree | 638 | 58.33 |
| 0714 | Best Time to Buy and Sell Stock with Transaction Fee | Medium | Array, Dynamic_Programming, Greedy, Dynamic_Programming_I_Day_8 | 417 | 90.91 |
| 0713 | Subarray Product Less Than K | Medium | Array, Sliding_Window, Algorithm_II_Day_5_Sliding_Window, Programming_Skills_II_Day_12, Udemy_Arrays | 336 | 92.11 |
| 0712 | Minimum ASCII Delete Sum for Two Strings | Medium | String, Dynamic_Programming | 176 | 100.00 |
| 0710 | Random Pick with Blacklist | Hard | Hash_Table, Math, Sorting, Binary_Search, Randomized | 632 | 100.00 |
| 0709 | To Lower Case | Easy | String, Programming_Skills_I_Day_9_String | 142 | 98.68 |
| 0707 | Design Linked List | Medium | Design, Linked_List, Data_Structure_II_Day_12_Linked_List, Programming_Skills_II_Day_19, Udemy_Linked_List | 243 | 100.00 |
| 0706 | Design HashMap | Easy | Array, Hash_Table, Design, Linked_List, Hash_Function, Data_Structure_II_Day_2_Array | 405 | 92.11 |
| 0705 | Design HashSet | Easy | Array, Hash_Table, Design, Linked_List, Hash_Function | 385 | 75.61 |
| 0704 | Binary Search | Easy | Array, Binary_Search, Algorithm_I_Day_1_Binary_Search, Binary_Search_I_Day_1, Level_1_Day_7_Binary_Search, Udemy_Binary_Search | 261 | 77.91 |
| 0703 | Kth Largest Element in a Stream | Easy | Tree, Binary_Tree, Design, Heap_Priority_Queue, Binary_Search_Tree, Data_Stream | 286 | 95.45 |
| 0701 | Insert into a Binary Search Tree | Medium | Tree, Binary_Tree, Binary_Search_Tree, Data_Structure_I_Day_13_Tree, Udemy_Tree_Stack_Queue | 311 | 79.03 |
| 0700 | Search in a Binary Search Tree | Easy | Tree, Binary_Tree, Binary_Search_Tree, Data_Structure_I_Day_13_Tree | 251 | 88.31 |
| 0699 | Falling Squares | Hard | Array, Ordered_Set, Segment_Tree | 293 | 100.00 |
| 0698 | Partition to K Equal Sum Subsets | Medium | Array, Dynamic_Programming, Bit_Manipulation, Backtracking, Bitmask, Memoization | 191 | 100.00 |
| 0697 | Degree of an Array | Easy | Array, Hash_Table, Udemy_Arrays | 289 | 84.62 |
| 0696 | Count Binary Substrings | Easy | String, Two_Pointers | 222 | 100.00 |
| 0695 | Max Area of Island | Medium | Array, Depth_First_Search, Breadth_First_Search, Matrix, Union_Find, Algorithm_I_Day_7_Breadth_First_Search_Depth_First_Search, Graph_Theory_I_Day_2_Matrix_Related_Problems | 324 | 24.06 |
| 0693 | Binary Number with Alternating Bits | Easy | Bit_Manipulation | 129 | 100.00 |
| 0692 | Top K Frequent Words | Medium | String, Hash_Table, Sorting, Heap_Priority_Queue, Counting, Trie, Bucket_Sort, Level_1_Day_15_Heap | 239 | 81.10 |
| 0691 | Stickers to Spell Word | Hard | Array, String, Dynamic_Programming, Bit_Manipulation, Backtracking, Bitmask | 249 | 100.00 |
| 0690 | Employee Importance | Medium | Hash_Table, Depth_First_Search, Breadth_First_Search | 255 | 100.00 |
| 0689 | Maximum Sum of 3 Non-Overlapping Subarrays | Hard | Array, Dynamic_Programming | 248 | 100.00 |
| 0688 | Knight Probability in Chessboard | Medium | Dynamic_Programming | 144 | 100.00 |
| 0687 | Longest Univalue Path | Medium | Depth_First_Search, Tree, Binary_Tree | 303 | 100.00 |
| 0686 | Repeated String Match | Medium | String, String_Matching | 164 | 100.00 |
| 0685 | Redundant Connection II | Hard | Depth_First_Search, Breadth_First_Search, Graph, Union_Find | 176 | 100.00 |
| 0684 | Redundant Connection | Medium | Depth_First_Search, Breadth_First_Search, Graph, Union_Find | 181 | 88.24 |
| 0682 | Baseball Game | Easy | Array, Stack, Simulation | 159 | 100.00 |
| 0680 | Valid Palindrome II | Easy | String, Greedy, Two_Pointers | 296 | 79.17 |
| 0679 | 24 Game | Hard | Array, Math, Backtracking | 175 | 100.00 |
| 0678 | Valid Parenthesis String | Medium | String, Dynamic_Programming, Greedy, Stack | 133 | 100.00 |
| 0677 | Map Sum Pairs | Medium | String, Hash_Table, Design, Trie | 197 | 80.00 |
| 0676 | Implement Magic Dictionary | Medium | String, Hash_Table, Design, Trie | 256 | 100.00 |
| 0675 | Cut Off Trees for Golf Event | Hard | Array, Breadth_First_Search, Matrix, Heap_Priority_Queue | 777 | 100.00 |
| 0674 | Longest Continuous Increasing Subsequence | Easy | Array | 201 | 84.21 |
| 0673 | Number of Longest Increasing Subsequence | Medium | Array, Dynamic_Programming, Segment_Tree, Binary_Indexed_Tree, Algorithm_II_Day_16_Dynamic_Programming | 226 | 91.67 |
| 0672 | Bulb Switcher II | Medium | Math, Depth_First_Search, Breadth_First_Search, Bit_Manipulation | 131 | 100.00 |
| 0671 | Second Minimum Node In a Binary Tree | Easy | Depth_First_Search, Tree, Binary_Tree | 128 | 100.00 |
| 0670 | Maximum Swap | Medium | Math, Greedy | 143 | 100.00 |
| 0669 | Trim a Binary Search Tree | Medium | Depth_First_Search, Tree, Binary_Tree, Binary_Search_Tree | 195 | 100.00 |
| 0668 | Kth Smallest Number in Multiplication Table | Hard | Math, Binary_Search | 151 | 100.00 |
| 0667 | Beautiful Arrangement II | Medium | Array, Math | 175 | 100.00 |
| 0665 | Non-decreasing Array | Medium | Array | 256 | 85.71 |
| 0664 | Strange Printer | Hard | String, Dynamic_Programming | 196 | 100.00 |
| 0662 | Maximum Width of Binary Tree | Medium | Depth_First_Search, Breadth_First_Search, Tree, Binary_Tree | 189 | 75.00 |
| 0661 | Image Smoother | Easy | Array, Matrix | 352 | 100.00 |
| 0659 | Split Array into Consecutive Subsequences | Medium | Array, Hash_Table, Greedy, Heap_Priority_Queue | 352 | 100.00 |
| 0658 | Find K Closest Elements | Medium | Array, Sorting, Binary_Search, Two_Pointers, Heap_Priority_Queue, Binary_Search_II_Day_2 | 375 | 95.16 |
| 0657 | Robot Return to Origin | Easy | String, Simulation | 186 | 100.00 |
| 0655 | Print Binary Tree | Medium | Depth_First_Search, Breadth_First_Search, Tree, Binary_Tree | 176 | 100.00 |
| 0654 | Maximum Binary Tree | Medium | Array, Tree, Binary_Tree, Stack, Monotonic_Stack, Divide_and_Conquer | 271 | 90.00 |
| 0653 | Two Sum IV - Input is a BST | Easy | Hash_Table, Depth_First_Search, Breadth_First_Search, Tree, Binary_Tree, Two_Pointers, Binary_Search_Tree, Data_Structure_I_Day_14_Tree | 231 | 96.08 |
| 0652 | Find Duplicate Subtrees | Medium | Hash_Table, Depth_First_Search, Tree, Binary_Tree | 266 | 76.00 |
| 0650 | 2 Keys Keyboard | Medium | Dynamic_Programming, Math | 115 | 100.00 |
| 0649 | Dota2 Senate | Medium | String, Greedy, Queue | 217 | 100.00 |
| 0648 | Replace Words | Medium | Array, String, Hash_Table, Trie | 392 | 100.00 |
| 0647 | Palindromic Substrings | Medium | Top_100_Liked_Questions, String, Dynamic_Programming | 266 | 67.83 |
| 0646 | Maximum Length of Pair Chain | Medium | Array, Dynamic_Programming, Sorting, Greedy | 249 | 100.00 |
| 0645 | Set Mismatch | Easy | Array, Hash_Table, Sorting, Bit_Manipulation | 246 | 88.46 |
| 0643 | Maximum Average Subarray I | Easy | Array, Sliding_Window | 494 | 98.65 |
| 0641 | Design Circular Deque | Medium | Array, Design, Linked_List, Queue | 232 | 100.00 |
| 0640 | Solve the Equation | Medium | String, Math, Simulation | 170 | 66.67 |
| 0639 | Decode Ways II | Hard | String, Dynamic_Programming | 259 | 100.00 |
| 0638 | Shopping Offers | Medium | Array, Dynamic_Programming, Bit_Manipulation, Backtracking, Bitmask, Memoization | 195 | 100.00 |
| 0637 | Average of Levels in Binary Tree | Easy | Depth_First_Search, Breadth_First_Search, Tree, Binary_Tree | 249 | 100.00 |
| 0636 | Exclusive Time of Functions | Medium | Array, Stack | 270 | 80.00 |
| 0633 | Sum of Square Numbers | Medium | Math, Binary_Search, Two_Pointers, Binary_Search_I_Day_10 | 126 | 100.00 |
| 0632 | Smallest Range Covering Elements from K Lists | Hard | Array, Hash_Table, Sorting, Greedy, Heap_Priority_Queue, Sliding_Window | 399 | 83.33 |
| 0630 | Course Schedule III | Hard | Array, Greedy, Heap_Priority_Queue | 536 | 100.00 |
| 0629 | K Inverse Pairs Array | Hard | Dynamic_Programming | 155 | 100.00 |
| 0628 | Maximum Product of Three Numbers | Easy | Array, Math, Sorting | 276 | 97.30 |
| 0627 | Swap Salary | Easy | Database, SQL_I_Day_2_Select_and_Order | 400 | 51.04 |
| 0626 | Exchange Seats | Medium | Database | 502 | 50.56 |
| 0623 | Add One Row to Tree | Medium | Depth_First_Search, Breadth_First_Search, Tree, Binary_Tree | 202 | 100.00 |
| 0622 | Design Circular Queue | Medium | Array, Design, Linked_List, Queue, Programming_Skills_II_Day_20 | 234 | 92.68 |
| 0621 | Task Scheduler | Medium | Array, Hash_Table, Sorting, Greedy, Heap_Priority_Queue, Counting, Level_2_Day_5_Greedy | 266 | 98.36 |
| 0620 | Not Boring Movies | Easy | Database | 305 | 59.80 |
| 0617 | Merge Two Binary Trees | Easy | Depth_First_Search, Breadth_First_Search, Tree, Binary_Tree, Algorithm_I_Day_8_Breadth_First_Search_Depth_First_Search | 243 | 72.83 |
| 0611 | Valid Triangle Number | Medium | Array, Sorting, Greedy, Binary_Search, Two_Pointers, Binary_Search_II_Day_1 | 203 | 100.00 |
| 0609 | Find Duplicate File in System | Medium | Array, String, Hash_Table | 426 | 100.00 |
| 0608 | Tree Node | Medium | LeetCode_Curated_SQL_70, Database, SQL_I_Day_4_Union_and_Select | 794 | 48.38 |
| 0607 | Sales Person | Easy | LeetCode_Curated_SQL_70, Database, SQL_I_Day_6_Union | 2142 | 44.56 |
| 0606 | Construct String from Binary Tree | Easy | String, Depth_First_Search, Tree, Binary_Tree | 187 | 100.00 |
| 0605 | Can Place Flowers | Easy | Array, Greedy, Udemy_Arrays | 209 | 85.71 |
| 0601 | Human Traffic of Stadium | Hard | Database | 529 | 51.80 |
| 0600 | Non-negative Integers without Consecutive Ones | Hard | Dynamic_Programming | 142 | 100.00 |
| 0599 | Minimum Index Sum of Two Lists | Easy | Array, String, Hash_Table | 293 | 100.00 |
| 0598 | Range Addition II | Easy | Array, Math | 176 | 66.67 |
| 0596 | Classes More Than 5 Students | Easy | Database | 484 | 50.92 |
| 0595 | Big Countries | Easy | Database, SQL_I_Day_1_Select | 417 | 56.09 |
| 0594 | Longest Harmonious Subsequence | Easy | Array, Hash_Table, Sorting | 331 | 100.00 |
| 0593 | Valid Square | Medium | Math, Geometry | 161 | 83.33 |
| 0592 | Fraction Addition and Subtraction | Medium | String, Math, Simulation | 164 | 100.00 |
| 0591 | Tag Validator | Hard | String, Stack | 177 | 100.00 |
| 0590 | N-ary Tree Postorder Traversal | Easy | Depth_First_Search, Tree, Stack | 237 | 88.10 |
| 0589 | N-ary Tree Preorder Traversal | Easy | Depth_First_Search, Tree, Stack, Programming_Skills_I_Day_5_Function, Level_1_Day_6_Tree | 233 | 84.02 |
| 0587 | Erect the Fence | Hard | Array, Math, Geometry | 470 | 100.00 |
| 0586 | Customer Placing the Largest Number of Orders | Easy | LeetCode_Curated_SQL_70, Database, SQL_I_Day_8_Function | 768 | 44.85 |
| 0584 | Find Customer Referee | Easy | Database, SQL_I_Day_1_Select | 779 | 43.48 |
| 0583 | Delete Operation for Two Strings | Medium | String, Dynamic_Programming, Algorithm_II_Day_17_Dynamic_Programming | 197 | 100.00 |
| 0581 | Shortest Unsorted Continuous Subarray | Medium | Array, Sorting, Greedy, Two_Pointers, Stack, Monotonic_Stack | 246 | 100.00 |
| 0576 | Out of Boundary Paths | Medium | Dynamic_Programming | 153 | 100.00 |
| 0575 | Distribute Candies | Easy | Array, Hash_Table | 538 | 76.92 |
| 0572 | Subtree of Another Tree | Easy | Depth_First_Search, Tree, Binary_Tree, Hash_Function, String_Matching, Algorithm_II_Day_7_Breadth_First_Search_Depth_First_Search | 214 | 92.39 |
| 0567 | Permutation in String | Medium | String, Hash_Table, Two_Pointers, Sliding_Window, Algorithm_I_Day_6_Sliding_Window | 169 | 100.00 |
| 0566 | Reshape the Matrix | Easy | Array, Matrix, Simulation, Data_Structure_I_Day_4_Array, Programming_Skills_I_Day_7_Array | 239 | 99.05 |
| 0565 | Array Nesting | Medium | Array, Depth_First_Search | 553 | 100.00 |
| 0564 | Find the Closest Palindrome | Hard | String, Math | 179 | 100.00 |
| 0563 | Binary Tree Tilt | Easy | Depth_First_Search, Tree, Binary_Tree | 197 | 100.00 |
| 0561 | Array Partition | Easy | Array, Sorting, Greedy, Counting_Sort | 337 | 90.48 |
| 0560 | Subarray Sum Equals K | Medium | Top_100_Liked_Questions, Array, Hash_Table, Prefix_Sum, Data_Structure_II_Day_5_Array | 692 | 53.27 |
| 0559 | Maximum Depth of N-ary Tree | Easy | Depth_First_Search, Breadth_First_Search, Tree | 196 | 100.00 |
| 0558 | Logical OR of Two Binary Grids Represented as Quad-Trees | Medium | Tree, Divide_and_Conquer | 268 | 100.00 |
| 0557 | Reverse Words in a String III | Easy | String, Two_Pointers, Algorithm_I_Day_4_Two_Pointers | 215 | 98.10 |
| 0556 | Next Greater Element III | Medium | String, Math, Two_Pointers, Programming_Skills_II_Day_10 | 137 | 80.00 |
| 0554 | Brick Wall | Medium | Array, Hash_Table | 307 | 100.00 |
| 0553 | Optimal Division | Medium | Array, Dynamic_Programming, Math | 154 | 100.00 |
| 0552 | Student Attendance Record II | Hard | Dynamic_Programming | 151 | 100.00 |
| 0551 | Student Attendance Record I | Easy | String | 151 | 95.00 |
| 0547 | Number of Provinces | Medium | Depth_First_Search, Breadth_First_Search, Graph, Union_Find, Algorithm_II_Day_6_Breadth_First_Search_Depth_First_Search, Graph_Theory_I_Day_8_Standard_Traversal, Level_2_Day_19_Union_Find | 229 | 79.73 |
| 0546 | Remove Boxes | Hard | Array, Dynamic_Programming, Memoization | 283 | 100.00 |
| 0543 | Diameter of Binary Tree | Easy | Top_100_Liked_Questions, Depth_First_Search, Tree, Binary_Tree, Level_2_Day_7_Tree, Udemy_Tree_Stack_Queue | 307 | 43.93 |
| 0542 | 01 Matrix | Medium | Array, Dynamic_Programming, Breadth_First_Search, Matrix, Algorithm_I_Day_9_Breadth_First_Search_Depth_First_Search, Graph_Theory_I_Day_5_Matrix_Related_Problems | 441 | 94.06 |
| 0541 | Reverse String II | Easy | String, Two_Pointers | 200 | 83.33 |
| 0540 | Single Element in a Sorted Array | Medium | Array, Binary_Search, Binary_Search_II_Day_9 | 274 | 86.67 |
| 0539 | Minimum Time Difference | Medium | Array, String, Math, Sorting | 183 | 100.00 |
| 0538 | Convert BST to Greater Tree | Medium | Depth_First_Search, Tree, Binary_Tree, Binary_Search_Tree | 252 | 77.78 |
| 0537 | Complex Number Multiplication | Medium | String, Math, Simulation | 171 | 75.00 |
| 0535 | Encode and Decode TinyURL | Medium | String, Hash_Table, Design, Hash_Function | 183 | 81.25 |
| 0532 | K-diff Pairs in an Array | Medium | Array, Hash_Table, Sorting, Binary_Search, Two_Pointers, Udemy_Arrays | 230 | 84.62 |
| 0530 | Minimum Absolute Difference in BST | Easy | Depth_First_Search, Breadth_First_Search, Tree, Binary_Tree, Binary_Search_Tree | 209 | 86.96 |
| 0529 | Minesweeper | Medium | Array, Depth_First_Search, Breadth_First_Search, Matrix | 243 | 87.50 |
| 0528 | Random Pick with Weight | Medium | Math, Binary_Search, Prefix_Sum, Randomized, Binary_Search_II_Day_13 | 393 | 91.38 |
| 0526 | Beautiful Arrangement | Medium | Array, Dynamic_Programming, Bit_Manipulation, Backtracking, Bitmask | 107 | 100.00 |
| 0525 | Contiguous Array | Medium | Array, Hash_Table, Prefix_Sum | 471 | 100.00 |
| 0524 | Longest Word in Dictionary through Deleting | Medium | Array, String, Sorting, Two_Pointers | 307 | 100.00 |
| 0523 | Continuous Subarray Sum | Medium | Array, Hash_Table, Math, Prefix_Sum | 682 | 95.45 |
| 0522 | Longest Uncommon Subsequence II | Medium | Array, String, Hash_Table, Sorting, Two_Pointers | 163 | 100.00 |
| 0521 | Longest Uncommon Subsequence I | Easy | String | 146 | 88.89 |
| 0520 | Detect Capital | Easy | String | 161 | 84.54 |
| 0519 | Random Flip Matrix | Medium | Hash_Table, Math, Randomized, Reservoir_Sampling | 270 | 100.00 |
| 0518 | Coin Change II | Medium | Array, Dynamic_Programming, Dynamic_Programming_I_Day_20 | 139 | 100.00 |
| 0517 | Super Washing Machines | Hard | Array, Greedy | 210 | 100.00 |
| 0516 | Longest Palindromic Subsequence | Medium | String, Dynamic_Programming, Dynamic_Programming_I_Day_17 | 243 | 87.50 |
| 0515 | Find Largest Value in Each Tree Row | Medium | Depth_First_Search, Breadth_First_Search, Tree, Binary_Tree | 238 | 73.33 |
| 0514 | Freedom Trail | Hard | String, Dynamic_Programming, Depth_First_Search, Breadth_First_Search | 182 | 100.00 |
| 0513 | Find Bottom Left Tree Value | Medium | Depth_First_Search, Breadth_First_Search, Tree, Binary_Tree | 190 | 88.24 |
| 0511 | Game Play Analysis I | Easy | LeetCode_Curated_SQL_70, Database, SQL_I_Day_8_Function | 790 | 45.04 |
| 0509 | Fibonacci Number | Easy | Dynamic_Programming, Math, Recursion, Memoization, Dynamic_Programming_I_Day_1, Level_1_Day_10_Dynamic_Programming, Udemy_Dynamic_Programming | 139 | 82.72 |
| 0508 | Most Frequent Subtree Sum | Medium | Hash_Table, Depth_First_Search, Tree, Binary_Tree | 246 | 80.00 |
| 0507 | Perfect Number | Easy | Math | 172 | 81.82 |
| 0506 | Relative Ranks | Easy | Array, Sorting, Heap_Priority_Queue | 244 | 94.23 |
| 0504 | Base 7 | Easy | Math | 136 | 100.00 |
| 0503 | Next Greater Element II | Medium | Array, Stack, Monotonic_Stack, Programming_Skills_II_Day_10 | 331 | 92.68 |
| 0502 | IPO | Hard | Array, Sorting, Greedy, Heap_Priority_Queue | 799 | 54.55 |
| 0501 | Find Mode in Binary Search Tree | Easy | Depth_First_Search, Tree, Binary_Tree, Binary_Search_Tree | 235 | 86.67 |
| 0500 | Keyboard Row | Easy | Array, String, Hash_Table | 170 | 85.19 |
| 0498 | Diagonal Traverse | Medium | Array, Matrix, Simulation | 430 | 61.54 |
| 0497 | Random Point in Non-overlapping Rectangles | Medium | Math, Binary_Search, Prefix_Sum, Ordered_Set, Randomized, Reservoir_Sampling | 759 | 100.00 |
| 0496 | Next Greater Element I | Easy | Array, Hash_Table, Stack, Monotonic_Stack, Programming_Skills_I_Day_5_Function | 171 | 100.00 |
| 0495 | Teemo Attacking | Easy | Array, Simulation | 283 | 100.00 |
| 0494 | Target Sum | Medium | Top_100_Liked_Questions, Array, Dynamic_Programming, Backtracking | 308 | 89.61 |
| 0493 | Reverse Pairs | Hard | Array, Binary_Search, Ordered_Set, Divide_and_Conquer, Segment_Tree, Binary_Indexed_Tree, Merge_Sort | 887 | 66.67 |
| 0492 | Construct the Rectangle | Easy | Math | 202 | 88.89 |
| 0491 | Non-decreasing Subsequences | Medium | Array, Hash_Table, Bit_Manipulation, Backtracking | 499 | 100.00 |
| 0488 | Zuma Game | Hard | String, Dynamic_Programming, Breadth_First_Search, Memoization | 1727 | 100.00 |
| 0486 | Predict the Winner | Medium | Array, Dynamic_Programming, Math, Recursion, Game_Theory | 158 | 84.62 |
| 0485 | Max Consecutive Ones | Easy | Array | 272 | 88.46 |
| 0483 | Smallest Good Base | Hard | Math, Binary_Search | 164 | 100.00 |
| 0482 | License Key Formatting | Easy | String | 234 | 87.18 |
| 0481 | Magical String | Medium | String, Two_Pointers | 124 | 100.00 |
| 0480 | Sliding Window Median | Hard | Array, Hash_Table, Heap_Priority_Queue, Sliding_Window | 409 | 100.00 |
| 0479 | Largest Palindrome Product | Hard | Math | 147 | 100.00 |
| 0478 | Generate Random Point in a Circle | Medium | Math, Geometry, Randomized, Rejection_Sampling | 862 | 100.00 |
| 0477 | Total Hamming Distance | Medium | Array, Math, Bit_Manipulation | 298 | 100.00 |
| 0476 | Number Complement | Easy | Bit_Manipulation | 133 | 100.00 |
| 0475 | Heaters | Medium | Array, Sorting, Binary_Search, Two_Pointers | 356 | 87.50 |
| 0474 | Ones and Zeroes | Medium | Array, String, Dynamic_Programming | 204 | 100.00 |
| 0473 | Matchsticks to Square | Medium | Array, Dynamic_Programming, Bit_Manipulation, Backtracking, Bitmask | 255 | 100.00 |
| 0472 | Concatenated Words | Hard | Array, String, Dynamic_Programming, Depth_First_Search, Trie | 484 | 100.00 |
| 0470 | Implement Rand10() Using Rand7() | Medium | Math, Randomized, Probability_and_Statistics, Rejection_Sampling | 220 | 100.00 |
| 0468 | Validate IP Address | Medium | String | 192 | 62.50 |
| 0467 | Unique Substrings in Wraparound String | Medium | String, Dynamic_Programming | 197 | 100.00 |
| 0466 | Count The Repetitions | Hard | String, Dynamic_Programming | 147 | 100.00 |
| 0464 | Can I Win | Medium | Dynamic_Programming, Math, Bit_Manipulation, Bitmask, Memoization, Game_Theory | 213 | 100.00 |
| 0463 | Island Perimeter | Easy | Array, Depth_First_Search, Breadth_First_Search, Matrix | 381 | 98.04 |
| 0462 | Minimum Moves to Equal Array Elements II | Medium | Array, Math, Sorting | 210 | 100.00 |
| 0461 | Hamming Distance | Easy | Bit_Manipulation, Udemy_Bit_Manipulation | 150 | 96.15 |
| 0460 | LFU Cache | Hard | Hash_Table, Design, Linked_List, Doubly_Linked_List | 1143 | 100.00 |
| 0459 | Repeated Substring Pattern | Easy | String, String_Matching, Programming_Skills_II_Day_2 | 201 | 100.00 |
| 0458 | Poor Pigs | Hard | Dynamic_Programming, Math, Combinatorics | 133 | 80.00 |
| 0457 | Circular Array Loop | Medium | Array, Hash_Table, Two_Pointers | 143 | 100.00 |
| 0456 | 132 Pattern | Medium | Array, Binary_Search, Stack, Ordered_Set, Monotonic_Stack, Udemy_Arrays | 434 | 100.00 |
| 0455 | Assign Cookies | Easy | Array, Sorting, Greedy | 260 | 96.67 |
| 0454 | 4Sum II | Medium | Top_Interview_Questions, Array, Hash_Table | 660 | 85.71 |
| 0453 | Minimum Moves to Equal Array Elements | Medium | Array, Math | 282 | 100.00 |
| 0452 | Minimum Number of Arrows to Burst Balloons | Medium | Array, Sorting, Greedy | 934 | 100.00 |
| 0451 | Sort Characters By Frequency | Medium | String, Hash_Table, Sorting, Heap_Priority_Queue, Counting, Bucket_Sort, Data_Structure_II_Day_21_Heap_Priority_Queue | 288 | 81.72 |
| 0450 | Delete Node in a BST | Medium | Tree, Binary_Tree, Binary_Search_Tree, Data_Structure_II_Day_16_Tree | 257 | 84.62 |
| 0449 | Serialize and Deserialize BST | Medium | String, Depth_First_Search, Breadth_First_Search, Tree, Binary_Tree, Design, Binary_Search_Tree | 233 | 100.00 |
| 0448 | Find All Numbers Disappeared in an Array | Easy | Array, Hash_Table, Udemy_Arrays | 394 | 100.00 |
| 0447 | Number of Boomerangs | Medium | Array, Hash_Table, Math | 308 | 100.00 |
| 0446 | Arithmetic Slices II - Subsequence | Hard | Array, Dynamic_Programming | 312 | 100.00 |
| 0445 | Add Two Numbers II | Medium | Math, Stack, Linked_List, Programming_Skills_II_Day_15, Udemy_Linked_List | 240 | 82.61 |
| 0443 | String Compression | Medium | String, Two_Pointers | 198 | 92.68 |
| 0442 | Find All Duplicates in an Array | Medium | Array, Hash_Table, Udemy_Arrays | 480 | 73.81 |
| 0441 | Arranging Coins | Easy | Math, Binary_Search, Binary_Search_I_Day_6 | 150 | 84.21 |
| 0440 | K-th Smallest in Lexicographical Order | Hard | Trie | 149 | 100.00 |
| 0438 | Find All Anagrams in a String | Medium | Top_100_Liked_Questions, String, Hash_Table, Sliding_Window, Algorithm_II_Day_5_Sliding_Window, Programming_Skills_II_Day_12, Level_1_Day_12_Sliding_Window/Two_Pointer | 561 | 54.68 |
| 0437 | Path Sum III | Medium | Top_100_Liked_Questions, Depth_First_Search, Tree, Binary_Tree, Level_2_Day_7_Tree | 403 | 54.12 |
| 0436 | Find Right Interval | Medium | Array, Sorting, Binary_Search, Binary_Search_II_Day_11 | 333 | 100.00 |
| 0435 | Non-overlapping Intervals | Medium | Array, Dynamic_Programming, Sorting, Greedy, Data_Structure_II_Day_4_Array | 1040 | 85.07 |
| 0434 | Number of Segments in a String | Easy | String | 167 | 80.00 |
| 0433 | Minimum Genetic Mutation | Medium | String, Hash_Table, Breadth_First_Search, Graph_Theory_I_Day_12_Breadth_First_Search | 204 | 82.08 |
| 0432 | All O`one Data Structure | Hard | Hash_Table, Design, Linked_List, Doubly_Linked_List | 1200 | 100.00 |
| 0430 | Flatten a Multilevel Doubly Linked List | Medium | Depth_First_Search, Linked_List, Doubly_Linked_List | 194 | 97.44 |
| 0429 | N-ary Tree Level Order Traversal | Medium | Breadth_First_Search, Tree, Programming_Skills_II_Day_9 | 278 | 75.00 |
| 0427 | Construct Quad Tree | Medium | Array, Tree, Matrix, Divide_and_Conquer | 221 | 94.74 |
| 0424 | Longest Repeating Character Replacement | Medium | String, Hash_Table, Sliding_Window, Level_1_Day_12_Sliding_Window/Two_Pointer | 288 | 84.38 |
| 0423 | Reconstruct Original Digits from English | Medium | String, Hash_Table, Math | 349 | 100.00 |
| 0421 | Maximum XOR of Two Numbers in an Array | Medium | Array, Hash_Table, Bit_Manipulation, Trie | 710 | 100.00 |
| 0420 | Strong Password Checker | Hard | String, Greedy, Heap_Priority_Queue | 157 | 80.00 |
| 0419 | Battleships in a Board | Medium | Array, Depth_First_Search, Matrix | 273 | 76.92 |
| 0417 | Pacific Atlantic Water Flow | Medium | Array, Depth_First_Search, Breadth_First_Search, Matrix, Graph_Theory_I_Day_4_Matrix_Related_Problems, Level_2_Day_10_Graph/BFS/DFS, Udemy_Graph | 319 | 100.00 |
| 0416 | Partition Equal Subset Sum | Medium | Top_100_Liked_Questions, Array, Dynamic_Programming, Level_2_Day_13_Dynamic_Programming | 204 | 98.82 |
| 0415 | Add Strings | Easy | String, Math, Simulation, Data_Structure_II_Day_6_String | 296 | 76.00 |
| 0414 | Third Maximum Number | Easy | Array, Sorting | 317 | 73.00 |
| 0413 | Arithmetic Slices | Medium | Array, Dynamic_Programming, Algorithm_II_Day_14_Dynamic_Programming, Dynamic_Programming_I_Day_10 | 156 | 100.00 |
| 0412 | Fizz Buzz | Easy | Top_Interview_Questions, String, Math, Simulation, Udemy_Integers | 307 | 71.81 |
| 0410 | Split Array Largest Sum | Hard | Array, Dynamic_Programming, Greedy, Binary_Search | 165 | 100.00 |
| 0409 | Longest Palindrome | Easy | String, Hash_Table, Greedy, Data_Structure_II_Day_6_String, Level_1_Day_5_Greedy | 259 | 60.71 |
| 0407 | Trapping Rain Water II | Hard | Array, Breadth_First_Search, Matrix, Heap_Priority_Queue | 500 | 100.00 |
| 0406 | Queue Reconstruction by Height | Medium | Array, Sorting, Greedy, Segment_Tree, Binary_Indexed_Tree | 306 | 100.00 |
| 0405 | Convert a Number to Hexadecimal | Easy | Math, Bit_Manipulation | 132 | 100.00 |
| 0404 | Sum of Left Leaves | Easy | Depth_First_Search, Breadth_First_Search, Tree, Binary_Tree, Programming_Skills_I_Day_10_Linked_List_and_Tree | 173 | 86.05 |
| 0403 | Frog Jump | Hard | Array, Dynamic_Programming | 240 | 100.00 |
| 0402 | Remove K Digits | Medium | String, Greedy, Stack, Monotonic_Stack | 375 | 75.00 |
| 0401 | Binary Watch | Easy | Bit_Manipulation, Backtracking | 266 | 71.43 |
| 0400 | Nth Digit | Medium | Math, Binary_Search | 271 | 50.00 |
| 0399 | Evaluate Division | Medium | Array, Depth_First_Search, Breadth_First_Search, Graph, Union_Find, Shortest_Path | 183 | 91.49 |
| 0398 | Random Pick Index | Medium | Hash_Table, Math, Randomized, Reservoir_Sampling | 1091 | 75.00 |
| 0397 | Integer Replacement | Medium | Dynamic_Programming, Greedy, Bit_Manipulation, Memoization | 145 | 87.50 |
| 0396 | Rotate Function | Medium | Array, Dynamic_Programming, Math | 571 | 87.50 |
| 0395 | Longest Substring with At Least K Repeating Characters | Medium | Top_Interview_Questions, String, Hash_Table, Sliding_Window, Divide_and_Conquer | 274 | 66.67 |
| 0394 | Decode String | Medium | Top_100_Liked_Questions, String, Stack, Recursion, Level_1_Day_14_Stack, Udemy_Strings | 224 | 64.86 |
| 0393 | UTF-8 Validation | Medium | Array, Bit_Manipulation | 219 | 100.00 |
| 0392 | Is Subsequence | Easy | String, Dynamic_Programming, Two_Pointers, Dynamic_Programming_I_Day_19, Level_1_Day_2_String, Udemy_Two_Pointers | 156 | 87.74 |
| 0391 | Perfect Rectangle | Hard | Array, Line_Sweep | 897 | 100.00 |
| 0390 | Elimination Game | Medium | Math, Recursion | 319 | 55.56 |
| 0389 | Find the Difference | Easy | String, Hash_Table, Sorting, Bit_Manipulation, Programming_Skills_I_Day_8_String, Udemy_Bit_Manipulation | 256 | 64.81 |
| 0388 | Longest Absolute File Path | Medium | String, Depth_First_Search, Stack | 150 | 100.00 |
| 0387 | First Unique Character in a String | Easy | Top_Interview_Questions, String, Hash_Table, Counting, Queue, Data_Structure_I_Day_6_String | 369 | 82.68 |
| 0386 | Lexicographical Numbers | Medium | Depth_First_Search, Trie | 463 | 83.33 |
| 0385 | Mini Parser | Medium | String, Depth_First_Search, Stack | 210 | 100.00 |
| 0384 | Shuffle an Array | Medium | Top_Interview_Questions, Array, Math, Randomized, Algorithm_II_Day_20_Others | 940 | 72.09 |
| 0383 | Ransom Note | Easy | String, Hash_Table, Counting, Data_Structure_I_Day_6_String | 333 | 79.58 |
| 0382 | Linked List Random Node | Medium | Math, Linked_List, Randomized, Reservoir_Sampling | 283 | 100.00 |
| 0381 | Insert Delete GetRandom O(1) - Duplicates allowed | Hard | Array, Hash_Table, Math, Design, Randomized | 1313 | 50.00 |
| 0380 | Insert Delete GetRandom O(1) | Medium | Top_Interview_Questions, Array, Hash_Table, Math, Design, Randomized, Programming_Skills_II_Day_20 | 1326 | 68.23 |
| 0378 | Kth Smallest Element in a Sorted Matrix | Medium | Top_Interview_Questions, Array, Sorting, Binary_Search, Matrix, Heap_Priority_Queue | 522 | 59.78 |
| 0377 | Combination Sum IV | Medium | Array, Dynamic_Programming, Dynamic_Programming_I_Day_21 | 217 | 72.41 |
| 0376 | Wiggle Subsequence | Medium | Array, Dynamic_Programming, Greedy, Dynamic_Programming_I_Day_18 | 162 | 88.89 |
| 0375 | Guess Number Higher or Lower II | Medium | Dynamic_Programming, Math, Game_Theory | 235 | 75.00 |
| 0374 | Guess Number Higher or Lower | Easy | Binary_Search, Interactive, Binary_Search_I_Day_1 | 134 | 94.19 |
| 0373 | Find K Pairs with Smallest Sums | Medium | Array, Heap_Priority_Queue | 1809 | 80.95 |
| 0372 | Super Pow | Medium | Math, Divide_and_Conquer | 196 | 100.00 |
| 0371 | Sum of Two Integers | Medium | Top_Interview_Questions, Math, Bit_Manipulation, Udemy_Bit_Manipulation | 129 | 95.45 |
| 0368 | Largest Divisible Subset | Medium | Array, Dynamic_Programming, Math, Sorting | 412 | 73.33 |
| 0367 | Valid Perfect Square | Easy | Math, Binary_Search, Binary_Search_I_Day_3 | 137 | 94.55 |
| 0365 | Water and Jug Problem | Medium | Math, Depth_First_Search, Breadth_First_Search, Graph_Theory_I_Day_11_Breadth_First_Search | 130 | 100.00 |
| 0363 | Max Sum of Rectangle No Larger Than K | Hard | Array, Dynamic_Programming, Binary_Search, Matrix, Ordered_Set | 243 | 100.00 |
| 0357 | Count Numbers with Unique Digits | Medium | Dynamic_Programming, Math, Backtracking | 104 | 100.00 |
| 0355 | Design Twitter | Medium | Hash_Table, Design, Heap_Priority_Queue, Linked_List | 288 | 68.75 |
| 0354 | Russian Doll Envelopes | Hard | Array, Dynamic_Programming, Sorting, Binary_Search | 788 | 100.00 |
| 0352 | Data Stream as Disjoint Intervals | Hard | Binary_Search, Design, Ordered_Set | 905 | 75.00 |
| 0350 | Intersection of Two Arrays II | Easy | Top_Interview_Questions, Array, Hash_Table, Sorting, Binary_Search, Two_Pointers, Data_Structure_I_Day_3_Array, Binary_Search_I_Day_10 | 321 | 73.37 |
| 0349 | Intersection of Two Arrays | Easy | Array, Hash_Table, Sorting, Binary_Search, Two_Pointers | 346 | 66.99 |
| 0347 | Top K Frequent Elements | Medium | Top_100_Liked_Questions, Top_Interview_Questions, Array, Hash_Table, Sorting, Heap_Priority_Queue, Counting, Divide_and_Conquer, Quickselect, Bucket_Sort, Data_Structure_II_Day_20_Heap_Priority_Queue | 268 | 99.74 |
| 0345 | Reverse Vowels of a String | Easy | String, Two_Pointers | 349 | 80.63 |
| 0344 | Reverse String | Easy | Top_Interview_Questions, String, Two_Pointers, Recursion, Algorithm_I_Day_4_Two_Pointers, Udemy_Strings | 445 | 69.75 |
| 0343 | Integer Break | Medium | Dynamic_Programming, Math, Algorithm_II_Day_18_Dynamic_Programming, Dynamic_Programming_I_Day_21 | 218 | 63.89 |
| 0342 | Power of Four | Easy | Math, Bit_Manipulation, Recursion | 150 | 92.11 |
| 0341 | Flatten Nested List Iterator | Medium | Top_Interview_Questions, Depth_First_Search, Tree, Stack, Design, Queue, Iterator, Programming_Skills_II_Day_18 | 210 | 100.00 |
| 0338 | Counting Bits | Easy | Top_100_Liked_Questions, Dynamic_Programming, Bit_Manipulation, Udemy_Bit_Manipulation | 186 | 99.26 |
| 0337 | House Robber III | Medium | Dynamic_Programming, Depth_First_Search, Tree, Binary_Tree, Udemy_Tree_Stack_Queue | 282 | 84.62 |
| 0336 | Palindrome Pairs | Hard | Array, String, Hash_Table, Trie | 2451 | 67.33 |
| 0335 | Self Crossing | Hard | Array, Math, Geometry | 477 | 100.00 |
| 0334 | Increasing Triplet Subsequence | Medium | Top_Interview_Questions, Array, Greedy, Data_Structure_II_Day_5_Array | 672 | 60.61 |
| 0332 | Reconstruct Itinerary | Hard | Depth_First_Search, Graph, Eulerian_Circuit | 240 | 93.88 |
| 0331 | Verify Preorder Serialization of a Binary Tree | Medium | String, Tree, Binary_Tree, Stack | 335 | 70.00 |
| 0330 | Patching Array | Hard | Array, Greedy | 201 | 100.00 |
| 0329 | Longest Increasing Path in a Matrix | Hard | Top_Interview_Questions, Dynamic_Programming, Depth_First_Search, Breadth_First_Search, Graph, Memoization, Topological_Sort | 322 | 92.65 |
| 0328 | Odd Even Linked List | Medium | Top_Interview_Questions, Linked_List, Level_2_Day_4_Linked_List, Udemy_Linked_List | 216 | 86.96 |
| 0327 | Count of Range Sum | Hard | Array, Binary_Search, Ordered_Set, Divide_and_Conquer, Segment_Tree, Binary_Indexed_Tree, Merge_Sort | 638 | 100.00 |
| 0326 | Power of Three | Easy | Top_Interview_Questions, Math, Recursion | 413 | 76.12 |
| 0324 | Wiggle Sort II | Medium | Top_Interview_Questions, Array, Sorting, Divide_and_Conquer, Quickselect | 545 | 57.14 |
| 0322 | Coin Change | Medium | Top_100_Liked_Questions, Top_Interview_Questions, Array, Dynamic_Programming, Breadth_First_Search, Algorithm_II_Day_18_Dynamic_Programming, Dynamic_Programming_I_Day_20, Level_2_Day_12_Dynamic_Programming | 332 | 50.68 |
| 0321 | Create Maximum Number | Hard | Greedy, Stack, Monotonic_Stack | 209 | 100.00 |
| 0319 | Bulb Switcher | Medium | Math, Brainteaser | 214 | 77.78 |
| 0318 | Maximum Product of Word Lengths | Medium | Array, String, Bit_Manipulation | 477 | 100.00 |
| 0316 | Remove Duplicate Letters | Medium | String, Greedy, Stack, Monotonic_Stack | 291 | 81.82 |
| 0315 | Count of Smaller Numbers After Self | Hard | Top_Interview_Questions, Array, Binary_Search, Ordered_Set, Divide_and_Conquer, Segment_Tree, Binary_Indexed_Tree, Merge_Sort | 1282 | 88.46 |
| 0313 | Super Ugly Number | Medium | Array, Dynamic_Programming, Math | 330 | 100.00 |
| 0312 | Burst Balloons | Hard | Array, Dynamic_Programming | 210 | 100.00 |
| 0310 | Minimum Height Trees | Medium | Depth_First_Search, Breadth_First_Search, Graph, Topological_Sort | 521 | 97.56 |
| 0309 | Best Time to Buy and Sell Stock with Cooldown | Medium | Array, Dynamic_Programming, Dynamic_Programming_I_Day_8 | 272 | 73.33 |
| 0307 | Range Sum Query - Mutable | Medium | Array, Design, Segment_Tree, Binary_Indexed_Tree | 1729 | 78.79 |
| 0306 | Additive Number | Medium | String, Backtracking | 261 | 63.16 |
| 0304 | Range Sum Query 2D - Immutable | Medium | Array, Matrix, Design, Prefix_Sum, Dynamic_Programming_I_Day_14, Programming_Skills_II_Day_13, Udemy_2D_Arrays/Matrix | 1373 | 85.71 |
| 0303 | Range Sum Query - Immutable | Easy | Array, Design, Prefix_Sum, Programming_Skills_I_Day_12_Class_and_Object | 472 | 63.64 |
| 0301 | Remove Invalid Parentheses | Hard | String, Breadth_First_Search, Backtracking | 312 | 100.00 |
| 0300 | Longest Increasing Subsequence | Medium | Top_100_Liked_Questions, Top_Interview_Questions, Array, Dynamic_Programming, Binary_Search, Algorithm_II_Day_16_Dynamic_Programming, Binary_Search_II_Day_3, Dynamic_Programming_I_Day_18, Udemy_Dynamic_Programming | 318 | 82.28 |
| 0299 | Bulls and Cows | Medium | String, Hash_Table, Counting, Level_1_Day_13_Hashmap | 254 | 84.82 |
| 0297 | Serialize and Deserialize Binary Tree | Hard | Top_Interview_Questions, String, Depth_First_Search, Breadth_First_Search, Tree, Binary_Tree, Design, Data_Structure_II_Day_18_Tree, Udemy_Tree_Stack_Queue | 475 | 78.85 |
| 0295 | Find Median from Data Stream | Hard | Top_100_Liked_Questions, Top_Interview_Questions, Sorting, Two_Pointers, Design, Heap_Priority_Queue, Data_Stream | 2289 | 33.60 |
| 0292 | Nim Game | Easy | Math, Game_Theory, Brainteaser | 129 | 94.29 |
| 0290 | Word Pattern | Easy | String, Hash_Table, Data_Structure_II_Day_7_String | 177 | 89.55 |
| 0289 | Game of Life | Medium | Top_Interview_Questions, Array, Matrix, Simulation | 174 | 96.97 |
| 0287 | Find the Duplicate Number | Medium | Top_100_Liked_Questions, Top_Interview_Questions, Array, Binary_Search, Two_Pointers, Bit_Manipulation, Binary_Search_II_Day_5 | 656 | 66.21 |
| 0284 | Peeking Iterator | Medium | Array, Design, Iterator | 286 | 62.50 |
| 0283 | Move Zeroes | Easy | Top_100_Liked_Questions, Top_Interview_Questions, Array, Two_Pointers, Algorithm_I_Day_3_Two_Pointers, Programming_Skills_I_Day_6_Array, Udemy_Arrays | 516 | 79.07 |
| 0282 | Expression Add Operators | Hard | String, Math, Backtracking | 367 | 85.71 |
| 0279 | Perfect Squares | Medium | Top_Interview_Questions, Dynamic_Programming, Math, Breadth_First_Search, Dynamic_Programming_I_Day_21 | 176 | 98.80 |
| 0278 | First Bad Version | Easy | Binary_Search, Interactive, Algorithm_I_Day_1_Binary_Search, Binary_Search_I_Day_5, Level_1_Day_7_Binary_Search | 349 | 76.86 |
| 0275 | H-Index II | Medium | Array, Binary_Search, Binary_Search_II_Day_8 | 398 | 81.82 |
| 0274 | H-Index | Medium | Array, Sorting, Counting_Sort | 291 | 45.45 |
| 0273 | Integer to English Words | Hard | String, Math, Recursion, Udemy_Strings | 273 | 82.93 |
| 0268 | Missing Number | Easy | Top_Interview_Questions, Array, Hash_Table, Math, Sorting, Binary_Search, Bit_Manipulation | 380 | 83.49 |
| 0264 | Ugly Number II | Medium | Hash_Table, Dynamic_Programming, Math, Heap_Priority_Queue, Dynamic_Programming_I_Day_11 | 182 | 95.45 |
| 0263 | Ugly Number | Easy | Math | 243 | 64.10 |
| 0262 | Trips and Users | Hard | Database | 577 | 63.97 |
| 0260 | Single Number III | Medium | Array, Bit_Manipulation | 222 | 100.00 |
| 0258 | Add Digits | Easy | Math, Simulation, Number_Theory | 234 | 71.64 |
| 0257 | Binary Tree Paths | Easy | String, Depth_First_Search, Tree, Binary_Tree, Backtracking | 320 | 72.84 |
| 0242 | Valid Anagram | Easy | Top_Interview_Questions, String, Hash_Table, Sorting, Data_Structure_I_Day_6_String, Programming_Skills_I_Day_11_Containers_and_Libraries, Udemy_Strings | 251 | 87.65 |
| 0241 | Different Ways to Add Parentheses | Medium | String, Dynamic_Programming, Math, Recursion, Memoization | 294 | 73.47 |
| 0240 | Search a 2D Matrix II | Medium | Top_100_Liked_Questions, Top_Interview_Questions, Array, Binary_Search, Matrix, Divide_and_Conquer, Data_Structure_II_Day_4_Array, Binary_Search_II_Day_8 | 460 | 66.08 |
| 0239 | Sliding Window Maximum | Hard | Top_100_Liked_Questions, Top_Interview_Questions, Array, Heap_Priority_Queue, Sliding_Window, Queue, Monotonic_Queue, Udemy_Arrays | 1059 | 86.14 |
| 0238 | Product of Array Except Self | Medium | Top_100_Liked_Questions, Top_Interview_Questions, Array, Prefix_Sum, Data_Structure_II_Day_5_Array, Udemy_Arrays | 669 | 48.96 |
| 0237 | Delete Node in a Linked List | Easy | Top_Interview_Questions, Linked_List | 183 | 93.00 |
| 0236 | Lowest Common Ancestor of a Binary Tree | Medium | Top_100_Liked_Questions, Top_Interview_Questions, Depth_First_Search, Tree, Binary_Tree, Data_Structure_II_Day_18_Tree, Udemy_Tree_Stack_Queue | 386 | 45.21 |
| 0235 | Lowest Common Ancestor of a Binary Search Tree | Easy | Depth_First_Search, Tree, Binary_Tree, Binary_Search_Tree, Data_Structure_I_Day_14_Tree, Level_1_Day_8_Binary_Search_Tree | 404 | 75.59 |
| 0234 | Palindrome Linked List | Easy | Top_100_Liked_Questions, Top_Interview_Questions, Two_Pointers, Stack, Linked_List, Recursion, Level_2_Day_3_Linked_List, Udemy_Linked_List | 641 | 79.53 |
| 0233 | Number of Digit One | Hard | Dynamic_Programming, Math, Recursion | 129 | 100.00 |
| 0232 | Implement Queue using Stacks | Easy | Stack, Design, Queue, Data_Structure_I_Day_9_Stack_Queue, Programming_Skills_I_Day_11_Containers_and_Libraries, Level_2_Day_16_Design | 258 | 70.86 |
| 0231 | Power of Two | Easy | Math, Bit_Manipulation, Recursion, Algorithm_I_Day_13_Bit_Manipulation | 161 | 86.81 |
| 0230 | Kth Smallest Element in a BST | Medium | Top_100_Liked_Questions, Top_Interview_Questions, Depth_First_Search, Tree, Binary_Tree, Binary_Search_Tree, Data_Structure_II_Day_17_Tree, Level_2_Day_9_Binary_Search_Tree | 393 | 33.33 |
| 0229 | Majority Element II | Medium | Array, Hash_Table, Sorting, Counting | 408 | 71.21 |
| 0228 | Summary Ranges | Easy | Array | 169 | 91.89 |
| 0227 | Basic Calculator II | Medium | Top_Interview_Questions, String, Math, Stack, Level_2_Day_18_Stack | 383 | 62.50 |
| 0226 | Invert Binary Tree | Easy | Top_100_Liked_Questions, Depth_First_Search, Breadth_First_Search, Tree, Binary_Tree, Data_Structure_I_Day_12_Tree, Level_2_Day_6_Tree, Udemy_Tree_Stack_Queue | 233 | 54.90 |
| 0225 | Implement Stack using Queues | Easy | Stack, Design, Queue | 248 | 73.44 |
| 0224 | Basic Calculator | Hard | String, Math, Stack, Recursion | 294 | 93.33 |
| 0223 | Rectangle Area | Medium | Math, Geometry | 291 | 66.67 |
| 0222 | Count Complete Tree Nodes | | | | |
| 0221 | Maximal Square | Medium | Top_100_Liked_Questions, Array, Dynamic_Programming, Matrix, Dynamic_Programming_I_Day_16 | 614 | 44.00 |
| 0220 | Contains Duplicate III | Medium | Array, Sorting, Sliding_Window, Ordered_Set, Bucket_Sort | 921 | 72.22 |
| 0219 | Contains Duplicate II | Easy | Array, Hash_Table, Sliding_Window | 813 | 80.46 |
| 0218 | The Skyline Problem | Hard | Top_Interview_Questions, Array, Heap_Priority_Queue, Ordered_Set, Divide_and_Conquer, Segment_Tree, Binary_Indexed_Tree, Line_Sweep | 365 | 93.14 |
| 0217 | Contains Duplicate | Easy | Top_Interview_Questions, Array, Hash_Table, Sorting, Data_Structure_I_Day_1_Array, Programming_Skills_I_Day_11_Containers_and_Libraries, Udemy_Arrays | 719 | 73.49 |
| 0216 | Combination Sum III | Medium | Array, Backtracking, Udemy_Backtracking/Recursion | 175 | 90.91 |
| 0215 | Kth Largest Element in an Array | Medium | Top_100_Liked_Questions, Top_Interview_Questions, Array, Sorting, Heap_Priority_Queue, Divide_and_Conquer, Quickselect, Data_Structure_II_Day_20_Heap_Priority_Queue | 839 | 34.43 |
| 0214 | Shortest Palindrome | Hard | String, Hash_Function, String_Matching, Rolling_Hash | 278 | 100.00 |
| 0213 | House Robber II | Medium | Array, Dynamic_Programming, Algorithm_II_Day_12_Dynamic_Programming, Dynamic_Programming_I_Day_3, Udemy_Dynamic_Programming | 257 | 59.62 |
| 0212 | Word Search II | Hard | Top_Interview_Questions, Array, String, Matrix, Backtracking, Trie | 268 | 100.00 |
| 0211 | Design Add and Search Words Data Structure | Medium | String, Depth_First_Search, Design, Trie | 2256 | 87.04 |
| 0210 | Course Schedule II | Medium | Top_Interview_Questions, Depth_First_Search, Breadth_First_Search, Graph, Topological_Sort, Level_2_Day_11_Graph/BFS/DFS | 266 | 96.32 |
| 0209 | Minimum Size Subarray Sum | Medium | Array, Binary_Search, Prefix_Sum, Sliding_Window, Algorithm_II_Day_5_Sliding_Window, Binary_Search_II_Day_1 | 315 | 96.73 |
| 0208 | Implement Trie (Prefix Tree) | Medium | Top_100_Liked_Questions, Top_Interview_Questions, String, Hash_Table, Design, Trie, Level_2_Day_16_Design, Udemy_Trie_and_Heap | 689 | 61.00 |
| 0207 | Course Schedule | Medium | Top_100_Liked_Questions, Top_Interview_Questions, Depth_First_Search, Breadth_First_Search, Graph, Topological_Sort | 416 | 40.10 |
| 0206 | Reverse Linked List | Easy | Top_100_Liked_Questions, Top_Interview_Questions, Linked_List, Recursion, Data_Structure_I_Day_8_Linked_List, Algorithm_I_Day_10_Recursion_Backtracking, Level_1_Day_3_Linked_List, Udemy_Linked_List | 279 | 45.78 |
| 0205 | Isomorphic Strings | Easy | String, Hash_Table, Level_1_Day_2_String | 278 | 79.96 |
| 0204 | Count Primes | Medium | Top_Interview_Questions, Array, Math, Enumeration, Number_Theory | 360 | 96.61 |
| 0203 | Remove Linked List Elements | Easy | Linked_List, Recursion, Data_Structure_I_Day_7_Linked_List | 233 | 91.22 |
| 0202 | Happy Number | Easy | Top_Interview_Questions, Hash_Table, Math, Two_Pointers, Algorithm_II_Day_21_Others, Programming_Skills_I_Day_4_Loop, Level_2_Day_1_Implementation/Simulation | 261 | 45.08 |
| 0201 | Bitwise AND of Numbers Range | Medium | Bit_Manipulation, Algorithm_II_Day_19_Bit_Manipulation | 368 | 80.00 |
| 0200 | Number of Islands | Medium | Top_100_Liked_Questions, Top_Interview_Questions, Array, Depth_First_Search, Breadth_First_Search, Matrix, Union_Find, Algorithm_II_Day_6_Breadth_First_Search_Depth_First_Search, Graph_Theory_I_Day_1_Matrix_Related_Problems, Level_1_Day_9_Graph/BFS/DFS, Udemy_Graph | 252 | 95.41 |
| 0199 | Binary Tree Right Side View | Medium | Depth_First_Search, Breadth_First_Search, Tree, Binary_Tree, Data_Structure_II_Day_16_Tree, Level_2_Day_15_Tree | 194 | 92.89 |
| 0198 | House Robber | Medium | Top_100_Liked_Questions, Top_Interview_Questions, Array, Dynamic_Programming, Algorithm_I_Day_12_Dynamic_Programming, Dynamic_Programming_I_Day_3, Level_2_Day_12_Dynamic_Programming, Udemy_Dynamic_Programming | 156 | 92.24 |
| 0197 | Rising Temperature | Easy | Database, SQL_I_Day_6_Union | 394 | 94.15 |
| 0196 | Delete Duplicate Emails | Easy | Database, SQL_I_Day_2_Select_and_Order | 593 | 94.17 |
| 0195 | Tenth Line | Easy | Shell | 36 | 87.50 |
| 0194 | Transpose File | Medium | Shell | 461 | 33.47 |
| 0193 | Valid Phone Numbers | Easy | Shell | 98 | 88.64 |
| 0192 | Word Frequency | Medium | Shell | 114 | 73.60 |
| 0191 | Number of 1 Bits | Easy | Top_Interview_Questions, Bit_Manipulation, Algorithm_I_Day_13_Bit_Manipulation, Programming_Skills_I_Day_2_Operator, Udemy_Bit_Manipulation | 237 | 68.44 |
| 0190 | Reverse Bits | Easy | Top_Interview_Questions, Bit_Manipulation, Divide_and_Conquer, Algorithm_I_Day_14_Bit_Manipulation, Udemy_Bit_Manipulation | 198 | 81.82 |
| 0189 | Rotate Array | Medium | Top_100_Liked_Questions, Top_Interview_Questions, Array, Math, Two_Pointers, Algorithm_I_Day_2_Two_Pointers, Udemy_Arrays | 483 | 86.95 |
| 0188 | Best Time to Buy and Sell Stock IV | Hard | Array, Dynamic_Programming | 293 | 68.31 |
| 0187 | Repeated DNA Sequences | Medium | String, Hash_Table, Bit_Manipulation, Sliding_Window, Hash_Function, Rolling_Hash, Data_Structure_II_Day_9_String, Udemy_Strings | 319 | 79.03 |
| 0185 | Department Top Three Salaries | Hard | Database | 757 | 87.06 |
| 0184 | Department Highest Salary | Medium | Database | 637 | 76.01 |
| 0183 | Customers Who Never Order | Easy | Database, SQL_I_Day_1_Select | 712 | 33.67 |
| 0182 | Duplicate Emails | Easy | Database, SQL_I_Day_10_Where | 396 | 68.40 |
| 0181 | Employees Earning More Than Their Managers | Easy | Database | 351 | 94.75 |
| 0180 | Consecutive Numbers | Medium | Database | 695 | 38.05 |
| 0179 | Largest Number | Medium | Top_Interview_Questions, String, Sorting, Greedy | 380 | 43.40 |
| 0178 | Rank Scores | Medium | Database | 292 | 85.14 |
| 0177 | Nth Highest Salary | Medium | Database | 338 | 86.68 |
| 0176 | Second Highest Salary | Medium | Database, SQL_I_Day_4_Union_and_Select | 219 | 92.54 |
| 0175 | Combine Two Tables | Easy | Database, SQL_I_Day_5_Union | 473 | 54.97 |
| 0174 | Dungeon Game | Hard | Array, Dynamic_Programming, Matrix | 300 | 66.67 |
| 0173 | Binary Search Tree Iterator | Medium | Tree, Binary_Tree, Stack, Design, Binary_Search_Tree, Iterator, Data_Structure_II_Day_17_Tree, Programming_Skills_II_Day_16, Level_2_Day_9_Binary_Search_Tree | 563 | 46.91 |
| 0172 | Factorial Trailing Zeroes | Medium | Top_Interview_Questions, Math, Udemy_Integers | 220 | 67.65 |
| 0171 | Excel Sheet Column Number | Easy | Top_Interview_Questions, String, Math | 310 | 30.68 |
| 0169 | Majority Element | Easy | Top_100_Liked_Questions, Top_Interview_Questions, Array, Hash_Table, Sorting, Counting, Divide_and_Conquer, Data_Structure_II_Day_1_Array, Udemy_Famous_Algorithm | 460 | 51.25 |
| 0168 | Excel Sheet Column Title | Easy | String, Math | 208 | 66.07 |
| 0167 | Two Sum II - Input Array Is Sorted | Medium | Array, Binary_Search, Two_Pointers, Algorithm_I_Day_3_Two_Pointers, Binary_Search_I_Day_7 | 403 | 68.74 |
| 0166 | Fraction to Recurring Decimal | Medium | Top_Interview_Questions, String, Hash_Table, Math | 147 | 90.91 |
| 0165 | Compare Version Numbers | Medium | String, Two_Pointers | 144 | 100.00 |
| 0164 | Maximum Gap | Hard | Array, Sorting, Bucket_Sort, Radix_Sort | 991 | 68.00 |
| 0162 | Find Peak Element | Medium | Top_Interview_Questions, Array, Binary_Search, Algorithm_II_Day_2_Binary_Search, Binary_Search_II_Day_12 | 297 | 53.85 |
| 0160 | Intersection of Two Linked Lists | Easy | Top_100_Liked_Questions, Top_Interview_Questions, Hash_Table, Two_Pointers, Linked_List, Data_Structure_II_Day_11_Linked_List, Udemy_Linked_List | 262 | 83.50 |
| 0155 | Min Stack | Easy | Top_100_Liked_Questions, Top_Interview_Questions, Stack, Design, Data_Structure_II_Day_14_Stack_Queue, Programming_Skills_II_Day_18, Level_2_Day_16_Design, Udemy_Design | 331 | 84.88 |
| 0154 | Find Minimum in Rotated Sorted Array II | Hard | Array, Binary_Search, Binary_Search_II_Day_13 | 275 | 84.00 |
| 0153 | Find Minimum in Rotated Sorted Array | Medium | Top_100_Liked_Questions, Array, Binary_Search, Algorithm_II_Day_2_Binary_Search, Binary_Search_I_Day_12, Udemy_Binary_Search | 262 | 60.96 |
| 0152 | Maximum Product Subarray | Medium | Top_100_Liked_Questions, Top_Interview_Questions, Array, Dynamic_Programming, Dynamic_Programming_I_Day_6, Level_2_Day_13_Dynamic_Programming, Udemy_Dynamic_Programming | 253 | 88.42 |
| 0151 | Reverse Words in a String | Medium | String, Two_Pointers, Udemy_Strings | 206 | 98.90 |
| 0150 | Evaluate Reverse Polish Notation | Medium | Top_Interview_Questions, Array, Math, Stack, Programming_Skills_II_Day_3 | 233 | 88.82 |
| 0149 | Max Points on a Line | Hard | Top_Interview_Questions, Array, Hash_Table, Math, Geometry, Algorithm_II_Day_21_Others | 307 | 83.33 |
| 0148 | Sort List | Medium | Top_100_Liked_Questions, Top_Interview_Questions, Sorting, Two_Pointers, Linked_List, Divide_and_Conquer, Merge_Sort, Level_2_Day_4_Linked_List | 820 | 61.70 |
| 0147 | Insertion Sort List | Medium | Sorting, Linked_List | 385 | 52.00 |
| 0146 | LRU Cache | Medium | Top_100_Liked_Questions, Top_Interview_Questions, Hash_Table, Design, Linked_List, Doubly_Linked_List, Udemy_Linked_List | 1116 | 97.93 |
| 0145 | Binary Tree Postorder Traversal | Easy | Depth_First_Search, Tree, Binary_Tree, Stack, Data_Structure_I_Day_10_Tree, Udemy_Tree_Stack_Queue | 211 | 80.00 |
| 0144 | Binary Tree Preorder Traversal | Easy | Depth_First_Search, Tree, Binary_Tree, Stack, Data_Structure_I_Day_10_Tree, Udemy_Tree_Stack_Queue | 277 | 37.90 |
| 0143 | Reorder List | Medium | Two_Pointers, Stack, Linked_List, Recursion, Data_Structure_II_Day_13_Linked_List, Programming_Skills_II_Day_14 | 395 | 82.26 |
| 0142 | Linked List Cycle II | Medium | Top_100_Liked_Questions, Hash_Table, Two_Pointers, Linked_List, Data_Structure_II_Day_10_Linked_List, Level_1_Day_4_Linked_List, Udemy_Linked_List | 192 | 63.39 |
| 0141 | Linked List Cycle | Easy | Top_100_Liked_Questions, Top_Interview_Questions, Hash_Table, Two_Pointers, Linked_List, Data_Structure_I_Day_7_Linked_List, Udemy_Linked_List | 223 | 91.85 |
| 0140 | Word Break II | Hard | Top_Interview_Questions, String, Hash_Table, Dynamic_Programming, Backtracking, Trie, Memoization | 287 | 44.19 |
| 0139 | Word Break | Medium | Top_100_Liked_Questions, Top_Interview_Questions, String, Hash_Table, Dynamic_Programming, Trie, Memoization, Algorithm_II_Day_15_Dynamic_Programming, Dynamic_Programming_I_Day_9, Udemy_Dynamic_Programming | 197 | 87.17 |
| 0138 | Copy List with Random Pointer | Medium | Top_100_Liked_Questions, Top_Interview_Questions, Hash_Table, Linked_List, Programming_Skills_II_Day_14, Udemy_Linked_List | 274 | 80.58 |
| 0137 | Single Number II | Medium | Array, Bit_Manipulation | 344 | 64.29 |
| 0136 | Single Number | Easy | Top_100_Liked_Questions, Top_Interview_Questions, Array, Bit_Manipulation, Data_Structure_II_Day_1_Array, Algorithm_I_Day_14_Bit_Manipulation, Udemy_Integers | 344 | 83.63 |
| 0135 | Candy | Hard | Array, Greedy | 466 | 58.33 |
| 0134 | Gas Station | Medium | Top_Interview_Questions, Array, Greedy | 545 | 70.18 |
| 0133 | Clone Graph | Medium | Hash_Table, Depth_First_Search, Breadth_First_Search, Graph, Udemy_Graph | 351 | 60.91 |
| 0132 | Palindrome Partitioning II | Hard | String, Dynamic_Programming | 290 | 100.00 |
| 0131 | Palindrome Partitioning | Medium | Top_100_Liked_Questions, Top_Interview_Questions, String, Dynamic_Programming, Backtracking | 820 | 87.27 |
| 0130 | Surrounded Regions | Medium | Top_Interview_Questions, Array, Depth_First_Search, Breadth_First_Search, Matrix, Union_Find, Algorithm_II_Day_8_Breadth_First_Search_Depth_First_Search | 355 | 84.42 |
| 0129 | Sum Root to Leaf Numbers | Medium | Depth_First_Search, Tree, Binary_Tree | 237 | 52.50 |
| 0128 | Longest Consecutive Sequence | Medium | Top_100_Liked_Questions, Top_Interview_Questions, Array, Hash_Table, Union_Find | 460 | 97.77 |
| 0127 | Word Ladder | Hard | Top_Interview_Questions, String, Hash_Table, Breadth_First_Search, Graph_Theory_I_Day_12_Breadth_First_Search | 396 | 98.68 |
| 0126 | Word Ladder II | Hard | String, Hash_Table, Breadth_First_Search, Backtracking | 418 | 51.45 |
| 0125 | Valid Palindrome | Easy | Top_Interview_Questions, String, Two_Pointers, Udemy_Two_Pointers | 353 | 52.06 |
| 0124 | Binary Tree Maximum Path Sum | Hard | Top_100_Liked_Questions, Top_Interview_Questions, Dynamic_Programming, Depth_First_Search, Tree, Binary_Tree, Udemy_Tree_Stack_Queue | 331 | 74.42 |
| 0123 | Best Time to Buy and Sell Stock III | Hard | Array, Dynamic_Programming | 585 | 95.24 |
| 0122 | Best Time to Buy and Sell Stock II | Medium | Top_Interview_Questions, Array, Dynamic_Programming, Greedy, Dynamic_Programming_I_Day_7, Udemy_Arrays | 197 | 95.10 |
| 0121 | Best Time to Buy and Sell Stock | Easy | Top_100_Liked_Questions, Top_Interview_Questions, Array, Dynamic_Programming, Data_Structure_I_Day_3_Array, Dynamic_Programming_I_Day_7, Level_1_Day_5_Greedy, Udemy_Arrays | 609 | 94.06 |
| 0120 | Triangle | Medium | Array, Dynamic_Programming, Algorithm_I_Day_12_Dynamic_Programming, Dynamic_Programming_I_Day_13, Udemy_Dynamic_Programming | 194 | 97.87 |
| 0119 | Pascal's Triangle II | Easy | Array, Dynamic_Programming, Data_Structure_II_Day_3_Array, Dynamic_Programming_I_Day_12, Udemy_Dynamic_Programming | 157 | 97.27 |
| 0118 | Pascal's Triangle | Easy | Top_Interview_Questions, Array, Dynamic_Programming, Data_Structure_I_Day_4_Array, Dynamic_Programming_I_Day_12, Udemy_Dynamic_Programming | 277 | 33.22 |
| 0117 | Populating Next Right Pointers in Each Node II | Medium | Depth_First_Search, Breadth_First_Search, Tree, Binary_Tree, Linked_List, Algorithm_II_Day_7_Breadth_First_Search_Depth_First_Search | 199 | 94.67 |
| 0116 | Populating Next Right Pointers in Each Node | Medium | Top_Interview_Questions, Depth_First_Search, Breadth_First_Search, Tree, Binary_Tree, Linked_List, Algorithm_I_Day_8_Breadth_First_Search_Depth_First_Search | 355 | 69.02 |
| 0115 | Distinct Subsequences | Hard | String, Dynamic_Programming | 285 | 88.89 |
| 0114 | Flatten Binary Tree to Linked List | Medium | Top_100_Liked_Questions, Depth_First_Search, Tree, Binary_Tree, Stack, Linked_List, Udemy_Linked_List | 191 | 93.10 |
| 0113 | Path Sum II | Medium | Depth_First_Search, Tree, Binary_Tree, Backtracking, Data_Structure_II_Day_16_Tree | 364 | 78.67 |
| 0112 | Path Sum | Easy | Depth_First_Search, Breadth_First_Search, Tree, Binary_Tree, Data_Structure_I_Day_12_Tree | 322 | 36.41 |
| 0111 | Minimum Depth of Binary Tree | Easy | Depth_First_Search, Breadth_First_Search, Tree, Binary_Tree, Udemy_Tree_Stack_Queue | 525 | 90.51 |
| 0110 | Balanced Binary Tree | Easy | Depth_First_Search, Tree, Binary_Tree, Programming_Skills_II_Day_2, Level_2_Day_6_Tree, Udemy_Tree_Stack_Queue | 310 | 63.63 |
| 0109 | Convert Sorted List to Binary Search Tree | Medium | Tree, Binary_Tree, Linked_List, Binary_Search_Tree, Divide_and_Conquer | 376 | 59.26 |
| 0108 | Convert Sorted Array to Binary Search Tree | Easy | Top_Interview_Questions, Array, Tree, Binary_Tree, Binary_Search_Tree, Divide_and_Conquer, Data_Structure_II_Day_15_Tree, Level_2_Day_9_Binary_Search_Tree, Udemy_Tree_Stack_Queue | 334 | 35.39 |
| 0107 | Binary Tree Level Order Traversal II | Medium | Breadth_First_Search, Tree, Binary_Tree | 204 | 98.04 |
| 0106 | Construct Binary Tree from Inorder and Postorder Traversal | Medium | Array, Hash_Table, Tree, Binary_Tree, Divide_and_Conquer | 358 | 61.29 |
| 0105 | Construct Binary Tree from Preorder and Inorder Traversal | Medium | Top_100_Liked_Questions, Top_Interview_Questions, Array, Hash_Table, Tree, Binary_Tree, Divide_and_Conquer, Data_Structure_II_Day_15_Tree | 370 | 58.31 |
| 0104 | Maximum Depth of Binary Tree | Easy | Top_100_Liked_Questions, Top_Interview_Questions, Depth_First_Search, Breadth_First_Search, Tree, Binary_Tree, Data_Structure_I_Day_11_Tree, Programming_Skills_I_Day_10_Linked_List_and_Tree, Udemy_Tree_Stack_Queue | 236 | 83.39 |
| 0103 | Binary Tree Zigzag Level Order Traversal | Medium | Top_Interview_Questions, Breadth_First_Search, Tree, Binary_Tree, Data_Structure_II_Day_15_Tree, Udemy_Tree_Stack_Queue | 316 | 34.25 |
| 0102 | Binary Tree Level Order Traversal | Medium | Top_100_Liked_Questions, Top_Interview_Questions, Breadth_First_Search, Tree, Binary_Tree, Data_Structure_I_Day_11_Tree, Level_1_Day_6_Tree, Udemy_Tree_Stack_Queue | 332 | 67.53 |
| 0101 | Symmetric Tree | Easy | Top_100_Liked_Questions, Top_Interview_Questions, Depth_First_Search, Breadth_First_Search, Tree, Binary_Tree, Data_Structure_I_Day_11_Tree, Level_2_Day_15_Tree | 190 | 91.36 |
| 0100 | Same Tree | Easy | Depth_First_Search, Breadth_First_Search, Tree, Binary_Tree, Level_2_Day_15_Tree, Udemy_Tree_Stack_Queue | 208 | 72.24 |
| 0099 | Recover Binary Search Tree | Medium | Depth_First_Search, Tree, Binary_Tree, Binary_Search_Tree | 492 | 39.39 |
| 0098 | Validate Binary Search Tree | Medium | Top_100_Liked_Questions, Top_Interview_Questions, Depth_First_Search, Tree, Binary_Tree, Binary_Search_Tree, Data_Structure_I_Day_14_Tree, Level_1_Day_8_Binary_Search_Tree, Udemy_Tree_Stack_Queue | 330 | 41.38 |
| 0097 | Interleaving String | Medium | String, Dynamic_Programming | 240 | 57.50 |
| 0096 | Unique Binary Search Trees | Medium | Top_100_Liked_Questions, Dynamic_Programming, Math, Tree, Binary_Tree, Binary_Search_Tree, Dynamic_Programming_I_Day_11 | 147 | 88.52 |
| 0095 | Unique Binary Search Trees II | Medium | Dynamic_Programming, Tree, Binary_Tree, Backtracking, Binary_Search_Tree | 360 | 41.38 |
| 0094 | Binary Tree Inorder Traversal | Easy | Top_100_Liked_Questions, Top_Interview_Questions, Depth_First_Search, Tree, Binary_Tree, Stack, Data_Structure_I_Day_10_Tree, Udemy_Tree_Stack_Queue | 269 | 38.80 |
| 0093 | Restore IP Addresses | Medium | String, Backtracking | 304 | 73.33 |
| 0092 | Reverse Linked List II | Medium | Linked_List | 191 | 82.35 |
| 0091 | Decode Ways | Medium | Top_Interview_Questions, String, Dynamic_Programming, Algorithm_II_Day_15_Dynamic_Programming, Dynamic_Programming_I_Day_10 | 237 | 76.88 |
| 0090 | Subsets II | Medium | Array, Bit_Manipulation, Backtracking, Algorithm_II_Day_9_Recursion_Backtracking | 366 | 58.09 |
| 0089 | Gray Code | Medium | Math, Bit_Manipulation, Backtracking | 273 | 100.00 |
| 0088 | Merge Sorted Array | Easy | Top_Interview_Questions, Array, Sorting, Two_Pointers, Data_Structure_I_Day_2_Array | 311 | 33.40 |
| 0087 | Scramble String | Hard | String, Dynamic_Programming | 366 | 85.00 |
| 0086 | Partition List | Medium | Two_Pointers, Linked_List | 172 | 94.00 |
| 0085 | Maximal Rectangle | Hard | Array, Dynamic_Programming, Matrix, Stack, Monotonic_Stack | 463 | 55.17 |
| 0084 | Largest Rectangle in Histogram | Hard | Top_100_Liked_Questions, Top_Interview_Questions, Array, Stack, Monotonic_Stack | 525 | 100.00 |
| 0083 | Remove Duplicates from Sorted List | Easy | Linked_List, Data_Structure_I_Day_8_Linked_List | 274 | 77.82 |
| 0082 | Remove Duplicates from Sorted List II | Medium | Two_Pointers, Linked_List, Data_Structure_II_Day_11_Linked_List, Algorithm_II_Day_3_Two_Pointers | 241 | 91.04 |
| 0081 | Search in Rotated Sorted Array II | Medium | Array, Binary_Search, Binary_Search_II_Day_12 | 352 | 42.31 |
| 0080 | Remove Duplicates from Sorted Array II | Medium | Array, Two_Pointers, Udemy_Arrays | 357 | 44.78 |
| 0079 | Word Search | Medium | Top_100_Liked_Questions, Top_Interview_Questions, Array, Matrix, Backtracking, Algorithm_II_Day_11_Recursion_Backtracking | 463 | 68.49 |
| 0078 | Subsets | Medium | Top_100_Liked_Questions, Top_Interview_Questions, Array, Bit_Manipulation, Backtracking, Algorithm_II_Day_9_Recursion_Backtracking, Udemy_Backtracking/Recursion | 191 | 97.44 |
| 0077 | Combinations | Medium | Backtracking, Algorithm_I_Day_11_Recursion_Backtracking | 244 | 100.00 |
| 0076 | Minimum Window Substring | Hard | Top_100_Liked_Questions, Top_Interview_Questions, String, Hash_Table, Sliding_Window, Level_2_Day_14_Sliding_Window/Two_Pointer | 346 | 85.20 |
| 0075 | Sort Colors | Medium | Top_100_Liked_Questions, Top_Interview_Questions, Array, Sorting, Two_Pointers, Data_Structure_II_Day_2_Array, Udemy_Arrays | 198 | 85.66 |
| 0074 | Search a 2D Matrix | Medium | Top_100_Liked_Questions, Array, Binary_Search, Matrix, Data_Structure_I_Day_5_Array, Algorithm_II_Day_1_Binary_Search, Binary_Search_I_Day_8, Level_2_Day_8_Binary_Search, Udemy_2D_Arrays/Matrix | 290 | 40.17 |
| 0073 | Set Matrix Zeroes | Medium | Top_100_Liked_Questions, Top_Interview_Questions, Array, Hash_Table, Matrix, Udemy_2D_Arrays/Matrix | 255 | 100.00 |
| 0072 | Edit Distance | Hard | Top_100_Liked_Questions, String, Dynamic_Programming, Algorithm_II_Day_18_Dynamic_Programming, Dynamic_Programming_I_Day_19, Udemy_Dynamic_Programming | 320 | 63.53 |
| 0071 | Simplify Path | Medium | String, Stack | 318 | 64.44 |
| 0070 | Climbing Stairs | Easy | Top_100_Liked_Questions, Top_Interview_Questions, Dynamic_Programming, Math, Memoization, Algorithm_I_Day_12_Dynamic_Programming, Dynamic_Programming_I_Day_2, Level_1_Day_10_Dynamic_Programming, Udemy_Dynamic_Programming | 127 | 97.06 |
| 0069 | Sqrt(x) | Easy | Top_Interview_Questions, Math, Binary_Search, Binary_Search_I_Day_4 | 153 | 95.75 |
| 0068 | Text Justification | Hard | Array, String, Simulation | 269 | 50.00 |
| 0067 | Add Binary | Easy | String, Math, Bit_Manipulation, Simulation, Programming_Skills_II_Day_5 | 327 | 32.67 |
| 0066 | Plus One | Easy | Top_Interview_Questions, Array, Math, Programming_Skills_II_Day_3, Udemy_Arrays | 303 | 35.18 |
| 0065 | Valid Number | Hard | String | 310 | 81.82 |
| 0064 | Minimum Path Sum | Medium | Top_100_Liked_Questions, Array, Dynamic_Programming, Matrix, Dynamic_Programming_I_Day_16, Udemy_Dynamic_Programming | 222 | 95.70 |
| 0063 | Unique Paths II | Medium | Array, Dynamic_Programming, Matrix, Dynamic_Programming_I_Day_15 | 187 | 84.62 |
| 0062 | Unique Paths | Medium | Top_100_Liked_Questions, Top_Interview_Questions, Dynamic_Programming, Math, Combinatorics, Algorithm_II_Day_13_Dynamic_Programming, Dynamic_Programming_I_Day_15, Level_1_Day_11_Dynamic_Programming | 209 | 49.18 |
| 0061 | Rotate List | Medium | Two_Pointers, Linked_List, Programming_Skills_II_Day_16, Udemy_Linked_List | 193 | 92.16 |
| 0060 | Permutation Sequence | Hard | Math, Recursion | 146 | 100.00 |
| 0059 | Spiral Matrix II | Medium | Array, Matrix, Simulation, Data_Structure_II_Day_3_Array | 153 | 100.00 |
| 0058 | Length of Last Word | Easy | String, Programming_Skills_II_Day_6, Udemy_Arrays | 243 | 63.33 |
| 0057 | Insert Interval | Medium | Array, Level_2_Day_17_Interval | 257 | 99.52 |
| 0056 | Merge Intervals | Medium | Top_100_Liked_Questions, Top_Interview_Questions, Array, Sorting, Data_Structure_II_Day_2_Array, Level_2_Day_17_Interval, Udemy_2D_Arrays/Matrix | 320 | 94.22 |
| 0055 | Jump Game | Medium | Top_100_Liked_Questions, Top_Interview_Questions, Array, Dynamic_Programming, Greedy, Algorithm_II_Day_12_Dynamic_Programming, Dynamic_Programming_I_Day_4, Udemy_Arrays | 670 | 66.67 |
| 0054 | Spiral Matrix | Medium | Top_Interview_Questions, Array, Matrix, Simulation, Programming_Skills_II_Day_8, Level_2_Day_1_Implementation/Simulation, Udemy_2D_Arrays/Matrix | 224 | 62.50 |
| 0053 | Maximum Subarray | Easy | Top_100_Liked_Questions, Top_Interview_Questions, Array, Dynamic_Programming, Divide_and_Conquer, Data_Structure_I_Day_1_Array, Dynamic_Programming_I_Day_5, Udemy_Famous_Algorithm | 662 | 82.48 |
| 0052 | N-Queens II | Hard | Backtracking | 231 | 80.00 |
| 0051 | N-Queens | Hard | Top_100_Liked_Questions, Array, Backtracking | 243 | 95.10 |
| 0050 | Pow(x, n) | Medium | Top_Interview_Questions, Math, Recursion, Udemy_Integers | 264 | 52.98 |
| 0049 | Group Anagrams | Medium | Top_100_Liked_Questions, Top_Interview_Questions, Array, String, Hash_Table, Sorting, Data_Structure_II_Day_8_String, Programming_Skills_II_Day_11, Udemy_Strings | 506 | 86.55 |
| 0048 | Rotate Image | Medium | Top_100_Liked_Questions, Top_Interview_Questions, Array, Math, Matrix, Data_Structure_II_Day_3_Array, Programming_Skills_II_Day_7, Udemy_2D_Arrays/Matrix | 287 | 46.50 |
| 0047 | Permutations II | Medium | Array, Backtracking, Algorithm_II_Day_10_Recursion_Backtracking | 406 | 76.36 |
| 0046 | Permutations | Medium | Top_100_Liked_Questions, Top_Interview_Questions, Array, Backtracking, Algorithm_I_Day_11_Recursion_Backtracking, Level_2_Day_20_Brute_Force/Backtracking, Udemy_Backtracking/Recursion | 186 | 100.00 |
| 0045 | Jump Game II | Medium | Top_100_Liked_Questions, Array, Dynamic_Programming, Greedy, Algorithm_II_Day_13_Dynamic_Programming, Dynamic_Programming_I_Day_4 | 227 | 98.14 |
| 0044 | Wildcard Matching | Hard | Top_Interview_Questions, String, Dynamic_Programming, Greedy, Recursion, Udemy_Dynamic_Programming | 401 | 86.11 |
| 0043 | Multiply Strings | Medium | String, Math, Simulation, Data_Structure_II_Day_8_String, Programming_Skills_II_Day_4, Level_2_Day_2_String | 390 | 56.25 |
| 0042 | Trapping Rain Water | Hard | Top_100_Liked_Questions, Top_Interview_Questions, Array, Dynamic_Programming, Two_Pointers, Stack, Monotonic_Stack, Dynamic_Programming_I_Day_9, Udemy_Two_Pointers | 196 | 100.00 |
| 0041 | First Missing Positive | Hard | Top_100_Liked_Questions, Top_Interview_Questions, Array, Hash_Table, Udemy_Arrays | 345 | 100.00 |
| 0040 | Combination Sum II | Medium | Array, Backtracking, Algorithm_II_Day_10_Recursion_Backtracking | 348 | 80.92 |
| 0039 | Combination Sum | Medium | Top_100_Liked_Questions, Array, Backtracking, Algorithm_II_Day_10_Recursion_Backtracking, Level_2_Day_20_Brute_Force/Backtracking, Udemy_Backtracking/Recursion | 317 | 86.85 |
| 0038 | Count and Say | Medium | Top_Interview_Questions, String | 317 | 41.11 |
| 0037 | Sudoku Solver | Hard | Array, Matrix, Backtracking | 294 | 79.69 |
| 0036 | Valid Sudoku | Medium | Top_Interview_Questions, Array, Hash_Table, Matrix, Data_Structure_I_Day_5_Array | 346 | 65.03 |
| 0035 | Search Insert Position | Easy | Top_100_Liked_Questions, Array, Binary_Search, Algorithm_I_Day_1_Binary_Search, Binary_Search_I_Day_2 | 267 | 50.32 |
| 0034 | Find First and Last Position of Element in Sorted Array | Medium | Top_100_Liked_Questions, Top_Interview_Questions, Array, Binary_Search, Algorithm_II_Day_1_Binary_Search, Binary_Search_I_Day_5 | 228 | 83.38 |
| 0033 | Search in Rotated Sorted Array | Medium | Top_100_Liked_Questions, Top_Interview_Questions, Array, Binary_Search, Algorithm_II_Day_1_Binary_Search, Binary_Search_I_Day_11, Level_2_Day_8_Binary_Search, Udemy_Binary_Search | 184 | 86.08 |
| 0032 | Longest Valid Parentheses | Hard | Top_100_Liked_Questions, String, Dynamic_Programming, Stack | 215 | 95.71 |
| 0031 | Next Permutation | Medium | Top_100_Liked_Questions, Array, Two_Pointers | 211 | 94.23 |
| 0030 | Substring with Concatenation of All Words | Hard | String, Hash_Table, Sliding_Window | 441 | 85.84 |
| 0029 | Divide Two Integers | Medium | Top_Interview_Questions, Math, Bit_Manipulation, Udemy_Bit_Manipulation | 281 | 31.67 |
| 0028 | Find the Index of the First Occurrence in a String | Easy | Top_Interview_Questions, String, Two_Pointers, String_Matching, Programming_Skills_II_Day_1 | 257 | 32.35 |
| 0027 | Remove Element | Easy | Array, Two_Pointers | 293 | 32.19 |
| 0026 | Remove Duplicates from Sorted Array | Easy | Top_Interview_Questions, Array, Two_Pointers, Udemy_Two_Pointers | 361 | 77.19 |
| 0025 | Reverse Nodes in k-Group | Hard | Top_100_Liked_Questions, Linked_List, Recursion, Data_Structure_II_Day_13_Linked_List, Udemy_Linked_List | 194 | 87.72 |
| 0024 | Swap Nodes in Pairs | Medium | Top_100_Liked_Questions, Linked_List, Recursion, Data_Structure_II_Day_12_Linked_List, Udemy_Linked_List | 149 | 99.39 |
| 0023 | Merge k Sorted Lists | Hard | Top_100_Liked_Questions, Top_Interview_Questions, Heap_Priority_Queue, Linked_List, Divide_and_Conquer, Merge_Sort | 323 | 75.14 |
| 0022 | Generate Parentheses | Medium | Top_100_Liked_Questions, Top_Interview_Questions, String, Dynamic_Programming, Backtracking, Algorithm_II_Day_11_Recursion_Backtracking, Udemy_Backtracking/Recursion | 210 | 78.51 |
| 0021 | Merge Two Sorted Lists | Easy | Top_100_Liked_Questions, Top_Interview_Questions, Linked_List, Recursion, Data_Structure_I_Day_7_Linked_List, Algorithm_I_Day_10_Recursion_Backtracking, Level_1_Day_3_Linked_List, Udemy_Linked_List | 176 | 96.25 |
| 0020 | Valid Parentheses | Easy | Top_100_Liked_Questions, Top_Interview_Questions, String, Stack, Data_Structure_I_Day_9_Stack_Queue, Udemy_Strings | 226 | 72.53 |
| 0019 | Remove Nth Node From End of List | Medium | Top_100_Liked_Questions, Top_Interview_Questions, Two_Pointers, Linked_List, Algorithm_I_Day_5_Two_Pointers, Level_2_Day_3_Linked_List | 180 | 91.58 |
| 0018 | 4Sum | Medium | Array, Sorting, Two_Pointers | 221 | 100.00 |
| 0017 | Letter Combinations of a Phone Number | Medium | Top_100_Liked_Questions, Top_Interview_Questions, String, Hash_Table, Backtracking, Algorithm_II_Day_11_Recursion_Backtracking, Udemy_Backtracking/Recursion | 262 | 73.59 |
| 0016 | 3Sum Closest | Medium | Array, Sorting, Two_Pointers, Level_2_Day_14_Sliding_Window/Two_Pointer | 413 | 95.05 |
| 0015 | 3Sum | Medium | Top_100_Liked_Questions, Top_Interview_Questions, Array, Sorting, Two_Pointers, Data_Structure_II_Day_1_Array, Algorithm_II_Day_3_Two_Pointers, Udemy_Two_Pointers | 761 | 90.55 |
| 0014 | Longest Common Prefix | Easy | Top_Interview_Questions, String, Level_2_Day_2_String, Udemy_Strings | 209 | 88.86 |
| 0013 | Roman to Integer | Easy | Top_Interview_Questions, String, Hash_Table, Math | 358 | 75.16 |
| 0012 | Integer to Roman | Medium | String, Hash_Table, Math | 223 | 93.87 |
| 0011 | Container With Most Water | Medium | Top_100_Liked_Questions, Top_Interview_Questions, Array, Greedy, Two_Pointers, Algorithm_II_Day_4_Two_Pointers | 474 | 89.18 |
| 0010 | Regular Expression Matching | Hard | Top_100_Liked_Questions, Top_Interview_Questions, String, Dynamic_Programming, Recursion, Udemy_Dynamic_Programming | 292 | 58.58 |
| 0009 | Palindrome Number | Easy | Math, Udemy_Integers | 238 | 96.24 |
| 0008 | String to Integer (atoi) | Medium | Top_Interview_Questions, String | 196 | 96.46 |
| 0007 | Reverse Integer | Medium | Top_Interview_Questions, Math, Udemy_Integers | 245 | 60.32 |
| 0006 | Zigzag Conversion | Medium | String | 366 | 80.62 |
| 0005 | Longest Palindromic Substring | Medium | Top_100_Liked_Questions, Top_Interview_Questions, String, Dynamic_Programming, Data_Structure_II_Day_9_String, Algorithm_II_Day_14_Dynamic_Programming, Dynamic_Programming_I_Day_17, Udemy_Strings | 323 | 75.48 |
| 0004 | Median of Two Sorted Arrays | Hard | Top_100_Liked_Questions, Top_Interview_Questions, Array, Binary_Search, Divide_and_Conquer | 355 | 83.48 |
| 0003 | Longest Substring Without Repeating Characters | Medium | Top_100_Liked_Questions, Top_Interview_Questions, String, Hash_Table, Sliding_Window, Algorithm_I_Day_6_Sliding_Window, Level_2_Day_14_Sliding_Window/Two_Pointer, Udemy_Strings | 258 | 91.09 |
| 0002 | Add Two Numbers | Medium | Top_100_Liked_Questions, Top_Interview_Questions, Math, Linked_List, Recursion, Data_Structure_II_Day_10_Linked_List, Programming_Skills_II_Day_15 | 417 | 50.44 |
| 0001 | Two Sum | Easy | Top_100_Liked_Questions, Top_Interview_Questions, Array, Hash_Table, Data_Structure_I_Day_2_Array, Level_1_Day_13_Hashmap, Udemy_Arrays | 234 | 92.75 |
