Ruby-based LeetCode algorithm problem solutions, regularly updated.
- Algorithm II
- Binary Search I
- Binary Search II
- Dynamic Programming I
- Programming Skills I
- Programming Skills II
- Graph Theory I
- SQL I
- Level 1
- Level 2
- Udemy
- Data Structure I
- Data Structure II
- Algorithm I
| 0034 | Find First and Last Position of Element in Sorted Array | Medium | Top_100_Liked_Questions, Top_Interview_Questions, Array, Binary_Search, Big_O_Time_O(log_n)_Space_O(1) | 60 | 77.52 |
| 0033 | Search in Rotated Sorted Array | Medium | Top_100_Liked_Questions, Top_Interview_Questions, Array, Binary_Search, Big_O_Time_O(log_n)_Space_O(1) | 59 | 74.85 |
| 0074 | Search a 2D Matrix | Medium | Top_100_Liked_Questions, Array, Binary_Search, Matrix, Big_O_Time_O(endRow+endCol)_Space_O(1) | 50 | 97.83 |
| 0015 | 3Sum | Medium | Top_100_Liked_Questions, Top_Interview_Questions, Array, Sorting, Two_Pointers, Big_O_Time_O(n*log(n))_Space_O(n^2) | 659 | 83.74 |
| 0011 | Container With Most Water | Medium | Top_100_Liked_Questions, Top_Interview_Questions, Array, Greedy, Two_Pointers, Big_O_Time_O(n)_Space_O(1) | 114 | 95.98 |
| 0078 | Subsets | Medium | Top_100_Liked_Questions, Top_Interview_Questions, Array, Bit_Manipulation, Backtracking, Big_O_Time_O(2^n)_Space_O(n*2^n) | 63 | 70.43 |
| 0039 | Combination Sum | Medium | Top_100_Liked_Questions, Array, Backtracking, Big_O_Time_O(2^n)_Space_O(n+2^n) | 79 | 74.84 |
| 0017 | Letter Combinations of a Phone Number | Medium | Top_100_Liked_Questions, Top_Interview_Questions, String, Hash_Table, Backtracking, Big_O_Time_O(4^n)_Space_O(n) | 49 | 93.94 |
| 0022 | Generate Parentheses | Medium | Top_100_Liked_Questions, Top_Interview_Questions, String, Dynamic_Programming, Backtracking, Big_O_Time_O(2^n)_Space_O(n) | 43 | 100.00 |
| 0079 | Word Search | Medium | Top_100_Liked_Questions, Top_Interview_Questions, Array, Matrix, Backtracking, Big_O_Time_O(4^(m*n))_Space_O(m*n) | 56 | 100.00 |
| 0055 | Jump Game | Medium | Top_100_Liked_Questions, Top_Interview_Questions, Array, Dynamic_Programming, Greedy, Big_O_Time_O(n)_Space_O(1) | 88 | 95.88 |
| 0045 | Jump Game II | Medium | Top_100_Liked_Questions, Array, Dynamic_Programming, Greedy, Big_O_Time_O(n)_Space_O(1) | 68 | 75.23 |
| 0062 | Unique Paths | Medium | Top_100_Liked_Questions, Top_Interview_Questions, Dynamic_Programming, Math, Combinatorics, Big_O_Time_O(m*n)_Space_O(m*n) | 50 | 91.92 |
| 0005 | Longest Palindromic Substring | Medium | Top_100_Liked_Questions, Top_Interview_Questions, String, Dynamic_Programming, Big_O_Time_O(n)_Space_O(n) | 117 | 98.63 |
| 0072 | Edit Distance | Hard | Top_100_Liked_Questions, String, Dynamic_Programming, Big_O_Time_O(n^2)_Space_O(n2) | 139 | 73.91 |
| 0035 | Search Insert Position | Easy | Top_100_Liked_Questions, Array, Binary_Search, Big_O_Time_O(log_n)_Space_O(1) | 48 | 97.37 |
| 0034 | Find First and Last Position of Element in Sorted Array | Medium | Top_100_Liked_Questions, Top_Interview_Questions, Array, Binary_Search, Big_O_Time_O(log_n)_Space_O(1) | 60 | 77.52 |
| 0074 | Search a 2D Matrix | Medium | Top_100_Liked_Questions, Array, Binary_Search, Matrix, Big_O_Time_O(endRow+endCol)_Space_O(1) | 50 | 97.83 |
| 0033 | Search in Rotated Sorted Array | Medium | Top_100_Liked_Questions, Top_Interview_Questions, Array, Binary_Search, Big_O_Time_O(log_n)_Space_O(1) | 59 | 74.85 |
| 0070 | Climbing Stairs | Easy | Top_100_Liked_Questions, Top_Interview_Questions, Dynamic_Programming, Math, Memoization, Big_O_Time_O(n)_Space_O(n) | 48 | 96.01 |
| 0055 | Jump Game | Medium | Top_100_Liked_Questions, Top_Interview_Questions, Array, Dynamic_Programming, Greedy, Big_O_Time_O(n)_Space_O(1) | 88 | 95.88 |
| 0045 | Jump Game II | Medium | Top_100_Liked_Questions, Array, Dynamic_Programming, Greedy, Big_O_Time_O(n)_Space_O(1) | 68 | 75.23 |
| 0053 | Maximum Subarray | Easy | Top_100_Liked_Questions, Top_Interview_Questions, Array, Dynamic_Programming, Divide_and_Conquer, Big_O_Time_O(n)_Space_O(1) | 125 | 81.22 |
| 0121 | Best Time to Buy and Sell Stock | Easy | Top_100_Liked_Questions, Top_Interview_Questions, Array, Dynamic_Programming, Big_O_Time_O(N)_Space_O(1) | 147 | 80.21 |
| 0042 | Trapping Rain Water | Hard | Top_100_Liked_Questions, Top_Interview_Questions, Array, Dynamic_Programming, Two_Pointers, Stack, Monotonic_Stack, Big_O_Time_O(n)_Space_O(1) | 69 | 80.74 |
| 0096 | Unique Binary Search Trees | Medium | Top_100_Liked_Questions, Dynamic_Programming, Math, Tree, Binary_Tree, Binary_Search_Tree, Big_O_Time_O(n)_Space_O(1) | 57 | 61.54 |
| 0062 | Unique Paths | Medium | Top_100_Liked_Questions, Top_Interview_Questions, Dynamic_Programming, Math, Combinatorics, Big_O_Time_O(m*n)_Space_O(m*n) | 50 | 91.92 |
| 0064 | Minimum Path Sum | Medium | Top_100_Liked_Questions, Array, Dynamic_Programming, Matrix, Big_O_Time_O(m*n)_Space_O(m*n) | 78 | 52.50 |
| 0005 | Longest Palindromic Substring | Medium | Top_100_Liked_Questions, Top_Interview_Questions, String, Dynamic_Programming, Big_O_Time_O(n)_Space_O(n) | 117 | 98.63 |
| 0072 | Edit Distance | Hard | Top_100_Liked_Questions, String, Dynamic_Programming, Big_O_Time_O(n^2)_Space_O(n2) | 139 | 73.91 |
| 0104 | Maximum Depth of Binary Tree | Easy | Top_100_Liked_Questions, Top_Interview_Questions, Depth_First_Search, Breadth_First_Search, Tree, Binary_Tree, Big_O_Time_O(N)_Space_O(H) | 55 | 96.72 |
| 0048 | Rotate Image | Medium | Top_100_Liked_Questions, Top_Interview_Questions, Array, Math, Matrix, Big_O_Time_O(n^2)_Space_O(1) | 50 | 93.64 |
| 0049 | Group Anagrams | Medium | Top_100_Liked_Questions, Top_Interview_Questions, Array, String, Hash_Table, Sorting, Big_O_Time_O(n*k_log_k)_Space_O(n) | 154 | 83.69 |
| 0002 | Add Two Numbers | Medium | Top_100_Liked_Questions, Top_Interview_Questions, Math, Linked_List, Recursion, Big_O_Time_O(max(N,M))_Space_O(max(N,M)) | 68 | 97.48 |
| 0021 | Merge Two Sorted Lists | Easy | Top_100_Liked_Questions, Top_Interview_Questions, Linked_List, Recursion, Big_O_Time_O(m+n)_Space_O(m+n) | 66 | 59.01 |
| 0121 | Best Time to Buy and Sell Stock | Easy | Top_100_Liked_Questions, Top_Interview_Questions, Array, Dynamic_Programming, Big_O_Time_O(N)_Space_O(1) | 147 | 80.21 |
| 0102 | Binary Tree Level Order Traversal | Medium | Top_100_Liked_Questions, Top_Interview_Questions, Breadth_First_Search, Tree, Binary_Tree, Big_O_Time_O(N)_Space_O(N) | 66 | 76.43 |
| 0098 | Validate Binary Search Tree | Medium | Top_100_Liked_Questions, Top_Interview_Questions, Depth_First_Search, Tree, Binary_Tree, Binary_Search_Tree, Big_O_Time_O(N)_Space_O(log(N)) | 68 | 70.23 |
| 0070 | Climbing Stairs | Easy | Top_100_Liked_Questions, Top_Interview_Questions, Dynamic_Programming, Math, Memoization, Big_O_Time_O(n)_Space_O(n) | 48 | 96.01 |
| 0062 | Unique Paths | Medium | Top_100_Liked_Questions, Top_Interview_Questions, Dynamic_Programming, Math, Combinatorics, Big_O_Time_O(m*n)_Space_O(m*n) | 50 | 91.92 |
| 0001 | Two Sum | Easy | Top_100_Liked_Questions, Top_Interview_Questions, Array, Hash_Table, Big_O_Time_O(n)_Space_O(n) | 57 | 89.38 |
| 0019 | Remove Nth Node From End of List | Medium | Top_100_Liked_Questions, Top_Interview_Questions, Two_Pointers, Linked_List, Big_O_Time_O(L)_Space_O(L) | 51 | 95.27 |
| 0074 | Search a 2D Matrix | Medium | Top_100_Liked_Questions, Array, Binary_Search, Matrix, Big_O_Time_O(endRow+endCol)_Space_O(1) | 50 | 97.83 |
| 0033 | Search in Rotated Sorted Array | Medium | Top_100_Liked_Questions, Top_Interview_Questions, Array, Binary_Search, Big_O_Time_O(log_n)_Space_O(1) | 59 | 74.85 |
| 0003 | Longest Substring Without Repeating Characters | Medium | Top_100_Liked_Questions, Top_Interview_Questions, String, Hash_Table, Sliding_Window, Big_O_Time_O(n)_Space_O(1) | 94 | 85.62 |
| 0076 | Minimum Window Substring | Hard | Top_100_Liked_Questions, Top_Interview_Questions, String, Hash_Table, Sliding_Window, Big_O_Time_O(s.length())_Space_O(1) | 175 | 93.33 |
| 0101 | Symmetric Tree | Easy | Top_100_Liked_Questions, Top_Interview_Questions, Depth_First_Search, Breadth_First_Search, Tree, Binary_Tree, Big_O_Time_O(N)_Space_O(log(N)) | 58 | 91.34 |
| 0056 | Merge Intervals | Medium | Top_100_Liked_Questions, Top_Interview_Questions, Array, Sorting, Big_O_Time_O(n_log_n)_Space_O(n) | 103 | 74.70 |
| 0039 | Combination Sum | Medium | Top_100_Liked_Questions, Array, Backtracking, Big_O_Time_O(2^n)_Space_O(n+2^n) | 79 | 74.84 |
| 0046 | Permutations | Medium | Top_100_Liked_Questions, Top_Interview_Questions, Array, Backtracking, Big_O_Time_O(n*n!)_Space_O(n+n!) | 62 | 89.60 |
| 0136 | Single Number | Easy | Top_100_Liked_Questions, Top_Interview_Questions, Array, Bit_Manipulation, Big_O_Time_O(N)_Space_O(1) | 68 | 78.44 |
| 0007 | Reverse Integer | Medium | Top_Interview_Questions, Math | 58 | 75.27 |
| 0009 | Palindrome Number | Easy | Math | 83 | 74.19 |
| 0003 | Longest Substring Without Repeating Characters | Medium | Top_100_Liked_Questions, Top_Interview_Questions, String, Hash_Table, Sliding_Window, Big_O_Time_O(n)_Space_O(1) | 94 | 85.62 |
| 0020 | Valid Parentheses | Easy | Top_100_Liked_Questions, Top_Interview_Questions, String, Stack, Big_O_Time_O(n)_Space_O(n) | 53 | 90.52 |
| 0005 | Longest Palindromic Substring | Medium | Top_100_Liked_Questions, Top_Interview_Questions, String, Dynamic_Programming, Big_O_Time_O(n)_Space_O(n) | 117 | 98.63 |
| 0049 | Group Anagrams | Medium | Top_100_Liked_Questions, Top_Interview_Questions, Array, String, Hash_Table, Sorting, Big_O_Time_O(n*k_log_k)_Space_O(n) | 154 | 83.69 |
| 0033 | Search in Rotated Sorted Array | Medium | Top_100_Liked_Questions, Top_Interview_Questions, Array, Binary_Search, Big_O_Time_O(log_n)_Space_O(1) | 59 | 74.85 |
| 0121 | Best Time to Buy and Sell Stock | Easy | Top_100_Liked_Questions, Top_Interview_Questions, Array, Dynamic_Programming, Big_O_Time_O(N)_Space_O(1) | 147 | 80.21 |
| 0001 | Two Sum | Easy | Top_100_Liked_Questions, Top_Interview_Questions, Array, Hash_Table, Big_O_Time_O(n)_Space_O(n) | 57 | 89.38 |
| 0055 | Jump Game | Medium | Top_100_Liked_Questions, Top_Interview_Questions, Array, Dynamic_Programming, Greedy, Big_O_Time_O(n)_Space_O(1) | 88 | 95.88 |
| 0075 | Sort Colors | Medium | Top_100_Liked_Questions, Top_Interview_Questions, Array, Sorting, Two_Pointers, Big_O_Time_O(n)_Space_O(1) | 54 | 88.46 |
| 0041 | First Missing Positive | Hard | Top_100_Liked_Questions, Top_Interview_Questions, Array, Hash_Table, Big_O_Time_O(n)_Space_O(n) | 130 | 65.63 |
| 0042 | Trapping Rain Water | Hard | Top_100_Liked_Questions, Top_Interview_Questions, Array, Dynamic_Programming, Two_Pointers, Stack, Monotonic_Stack, Big_O_Time_O(n)_Space_O(1) | 69 | 80.74 |
| 0015 | 3Sum | Medium | Top_100_Liked_Questions, Top_Interview_Questions, Array, Sorting, Two_Pointers, Big_O_Time_O(n*log(n))_Space_O(n^2) | 659 | 83.74 |
| 0053 | Maximum Subarray | Easy | Top_100_Liked_Questions, Top_Interview_Questions, Array, Dynamic_Programming, Divide_and_Conquer, Big_O_Time_O(n)_Space_O(1) | 125 | 81.22 |
| 0074 | Search a 2D Matrix | Medium | Top_100_Liked_Questions, Array, Binary_Search, Matrix, Big_O_Time_O(endRow+endCol)_Space_O(1) | 50 | 97.83 |
| 0048 | Rotate Image | Medium | Top_100_Liked_Questions, Top_Interview_Questions, Array, Math, Matrix, Big_O_Time_O(n^2)_Space_O(1) | 50 | 93.64 |
| 0073 | Set Matrix Zeroes | Medium | Top_100_Liked_Questions, Top_Interview_Questions, Array, Hash_Table, Matrix, Big_O_Time_O(m*n)_Space_O(1) | 59 | 100.00 |
| 0056 | Merge Intervals | Medium | Top_100_Liked_Questions, Top_Interview_Questions, Array, Sorting, Big_O_Time_O(n_log_n)_Space_O(n) | 103 | 74.70 |
| 0114 | Flatten Binary Tree to Linked List | Medium | Top_100_Liked_Questions, Depth_First_Search, Tree, Binary_Tree, Stack, Linked_List, Big_O_Time_O(N)_Space_O(N) | 47 | 100.00 |
| 0024 | Swap Nodes in Pairs | Medium | Top_100_Liked_Questions, Linked_List, Recursion, Big_O_Time_O(n)_Space_O(1) | 59 | 76.00 |
| 0021 | Merge Two Sorted Lists | Easy | Top_100_Liked_Questions, Top_Interview_Questions, Linked_List, Recursion, Big_O_Time_O(m+n)_Space_O(m+n) | 66 | 59.01 |
| 0025 | Reverse Nodes in k-Group | Hard | Top_100_Liked_Questions, Linked_List, Recursion, Big_O_Time_O(n)_Space_O(k) | 62 | 91.67 |
| 0094 | Binary Tree Inorder Traversal | Easy | Top_100_Liked_Questions, Top_Interview_Questions, Depth_First_Search, Tree, Binary_Tree, Stack, Big_O_Time_O(n)_Space_O(n) | 56 | 84.00 |
| 0102 | Binary Tree Level Order Traversal | Medium | Top_100_Liked_Questions, Top_Interview_Questions, Breadth_First_Search, Tree, Binary_Tree, Big_O_Time_O(N)_Space_O(N) | 66 | 76.43 |
| 0104 | Maximum Depth of Binary Tree | Easy | Top_100_Liked_Questions, Top_Interview_Questions, Depth_First_Search, Breadth_First_Search, Tree, Binary_Tree, Big_O_Time_O(N)_Space_O(H) | 55 | 96.72 |
| 0124 | Binary Tree Maximum Path Sum | Hard | Top_100_Liked_Questions, Top_Interview_Questions, Dynamic_Programming, Depth_First_Search, Tree, Binary_Tree, Big_O_Time_O(N)_Space_O(N) | 71 | 98.00 |
| 0098 | Validate Binary Search Tree | Medium | Top_100_Liked_Questions, Top_Interview_Questions, Depth_First_Search, Tree, Binary_Tree, Binary_Search_Tree, Big_O_Time_O(N)_Space_O(log(N)) | 68 | 70.23 |
| 0070 | Climbing Stairs | Easy | Top_100_Liked_Questions, Top_Interview_Questions, Dynamic_Programming, Math, Memoization, Big_O_Time_O(n)_Space_O(n) | 48 | 96.01 |
| 0064 | Minimum Path Sum | Medium | Top_100_Liked_Questions, Array, Dynamic_Programming, Matrix, Big_O_Time_O(m*n)_Space_O(m*n) | 78 | 52.50 |
| 0072 | Edit Distance | Hard | Top_100_Liked_Questions, String, Dynamic_Programming, Big_O_Time_O(n^2)_Space_O(n2) | 139 | 73.91 |
| 0010 | Regular Expression Matching | Hard | Top_100_Liked_Questions, Top_Interview_Questions, String, Dynamic_Programming, Recursion, Big_O_Time_O(m*n)_Space_O(m*n) | 66 | 94.44 |
| 0022 | Generate Parentheses | Medium | Top_100_Liked_Questions, Top_Interview_Questions, String, Dynamic_Programming, Backtracking, Big_O_Time_O(2^n)_Space_O(n) | 43 | 100.00 |
| 0039 | Combination Sum | Medium | Top_100_Liked_Questions, Array, Backtracking, Big_O_Time_O(2^n)_Space_O(n+2^n) | 79 | 74.84 |
| 0078 | Subsets | Medium | Top_100_Liked_Questions, Top_Interview_Questions, Array, Bit_Manipulation, Backtracking, Big_O_Time_O(2^n)_Space_O(n*2^n) | 63 | 70.43 |
| 0017 | Letter Combinations of a Phone Number | Medium | Top_100_Liked_Questions, Top_Interview_Questions, String, Hash_Table, Backtracking, Big_O_Time_O(4^n)_Space_O(n) | 49 | 93.94 |
| 0046 | Permutations | Medium | Top_100_Liked_Questions, Top_Interview_Questions, Array, Backtracking, Big_O_Time_O(n*n!)_Space_O(n+n!) | 62 | 89.60 |
| 0053 | Maximum Subarray | Easy | Top_100_Liked_Questions, Top_Interview_Questions, Array, Dynamic_Programming, Divide_and_Conquer, Big_O_Time_O(n)_Space_O(1) | 125 | 81.22 |
| 0001 | Two Sum | Easy | Top_100_Liked_Questions, Top_Interview_Questions, Array, Hash_Table, Big_O_Time_O(n)_Space_O(n) | 57 | 89.38 |
| 0121 | Best Time to Buy and Sell Stock | Easy | Top_100_Liked_Questions, Top_Interview_Questions, Array, Dynamic_Programming, Big_O_Time_O(N)_Space_O(1) | 147 | 80.21 |
| 0074 | Search a 2D Matrix | Medium | Top_100_Liked_Questions, Array, Binary_Search, Matrix, Big_O_Time_O(endRow+endCol)_Space_O(1) | 50 | 97.83 |
| 0021 | Merge Two Sorted Lists | Easy | Top_100_Liked_Questions, Top_Interview_Questions, Linked_List, Recursion, Big_O_Time_O(m+n)_Space_O(m+n) | 66 | 59.01 |
| 0020 | Valid Parentheses | Easy | Top_100_Liked_Questions, Top_Interview_Questions, String, Stack, Big_O_Time_O(n)_Space_O(n) | 53 | 90.52 |
| 0094 | Binary Tree Inorder Traversal | Easy | Top_100_Liked_Questions, Top_Interview_Questions, Depth_First_Search, Tree, Binary_Tree, Stack, Big_O_Time_O(n)_Space_O(n) | 56 | 84.00 |
| 0102 | Binary Tree Level Order Traversal | Medium | Top_100_Liked_Questions, Top_Interview_Questions, Breadth_First_Search, Tree, Binary_Tree, Big_O_Time_O(N)_Space_O(N) | 66 | 76.43 |
| 0104 | Maximum Depth of Binary Tree | Easy | Top_100_Liked_Questions, Top_Interview_Questions, Depth_First_Search, Breadth_First_Search, Tree, Binary_Tree, Big_O_Time_O(N)_Space_O(H) | 55 | 96.72 |
| 0101 | Symmetric Tree | Easy | Top_100_Liked_Questions, Top_Interview_Questions, Depth_First_Search, Breadth_First_Search, Tree, Binary_Tree, Big_O_Time_O(N)_Space_O(log(N)) | 58 | 91.34 |
| 0098 | Validate Binary Search Tree | Medium | Top_100_Liked_Questions, Top_Interview_Questions, Depth_First_Search, Tree, Binary_Tree, Binary_Search_Tree, Big_O_Time_O(N)_Space_O(log(N)) | 68 | 70.23 |
| 0136 | Single Number | Easy | Top_100_Liked_Questions, Top_Interview_Questions, Array, Bit_Manipulation, Big_O_Time_O(N)_Space_O(1) | 68 | 78.44 |
| 0015 | 3Sum | Medium | Top_100_Liked_Questions, Top_Interview_Questions, Array, Sorting, Two_Pointers, Big_O_Time_O(n*log(n))_Space_O(n^2) | 659 | 83.74 |
| 0075 | Sort Colors | Medium | Top_100_Liked_Questions, Top_Interview_Questions, Array, Sorting, Two_Pointers, Big_O_Time_O(n)_Space_O(1) | 54 | 88.46 |
| 0056 | Merge Intervals | Medium | Top_100_Liked_Questions, Top_Interview_Questions, Array, Sorting, Big_O_Time_O(n_log_n)_Space_O(n) | 103 | 74.70 |
| 0048 | Rotate Image | Medium | Top_100_Liked_Questions, Top_Interview_Questions, Array, Math, Matrix, Big_O_Time_O(n^2)_Space_O(1) | 50 | 93.64 |
| 0049 | Group Anagrams | Medium | Top_100_Liked_Questions, Top_Interview_Questions, Array, String, Hash_Table, Sorting, Big_O_Time_O(n*k_log_k)_Space_O(n) | 154 | 83.69 |
| 0005 | Longest Palindromic Substring | Medium | Top_100_Liked_Questions, Top_Interview_Questions, String, Dynamic_Programming, Big_O_Time_O(n)_Space_O(n) | 117 | 98.63 |
| 0002 | Add Two Numbers | Medium | Top_100_Liked_Questions, Top_Interview_Questions, Math, Linked_List, Recursion, Big_O_Time_O(max(N,M))_Space_O(max(N,M)) | 68 | 97.48 |
| 0024 | Swap Nodes in Pairs | Medium | Top_100_Liked_Questions, Linked_List, Recursion, Big_O_Time_O(n)_Space_O(1) | 59 | 76.00 |
| 0025 | Reverse Nodes in k-Group | Hard | Top_100_Liked_Questions, Linked_List, Recursion, Big_O_Time_O(n)_Space_O(k) | 62 | 91.67 |
| 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, Big_O_Time_O(N)_Space_O(N) | 71 | 91.78 |
| 0035 | Search Insert Position | Easy | Top_100_Liked_Questions, Array, Binary_Search, Big_O_Time_O(log_n)_Space_O(1) | 48 | 97.37 |
| 0019 | Remove Nth Node From End of List | Medium | Top_100_Liked_Questions, Top_Interview_Questions, Two_Pointers, Linked_List, Big_O_Time_O(L)_Space_O(L) | 51 | 95.27 |
| 0003 | Longest Substring Without Repeating Characters | Medium | Top_100_Liked_Questions, Top_Interview_Questions, String, Hash_Table, Sliding_Window, Big_O_Time_O(n)_Space_O(1) | 94 | 85.62 |
| 0021 | Merge Two Sorted Lists | Easy | Top_100_Liked_Questions, Top_Interview_Questions, Linked_List, Recursion, Big_O_Time_O(m+n)_Space_O(m+n) | 66 | 59.01 |
| 0046 | Permutations | Medium | Top_100_Liked_Questions, Top_Interview_Questions, Array, Backtracking, Big_O_Time_O(n*n!)_Space_O(n+n!) | 62 | 89.60 |
| 0070 | Climbing Stairs | Easy | Top_100_Liked_Questions, Top_Interview_Questions, Dynamic_Programming, Math, Memoization, Big_O_Time_O(n)_Space_O(n) | 48 | 96.01 |
| 0136 | Single Number | Easy | Top_100_Liked_Questions, Top_Interview_Questions, Array, Bit_Manipulation, Big_O_Time_O(N)_Space_O(1) | 68 | 78.44 |
| # | Title | Difficulty | Tag | Time, ms | Time, % |
|---|---|---|---|---|---|
| 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, Big_O_Time_O(N)_Space_O(1) | 68 | 78.44 |
| 0131 | Palindrome Partitioning | Medium | Top_100_Liked_Questions, Top_Interview_Questions, String, Dynamic_Programming, Backtracking, Big_O_Time_O(N*2^N)_Space_O(2^N*N) | 1192 | 63.64 |
| 0128 | Longest Consecutive Sequence | Medium | Top_100_Liked_Questions, Top_Interview_Questions, Array, Hash_Table, Union_Find, Big_O_Time_O(N_log_N)_Space_O(1) | 135 | 91.36 |
| 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, Big_O_Time_O(N)_Space_O(N) | 71 | 98.00 |
| 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, Big_O_Time_O(N)_Space_O(1) | 147 | 80.21 |
| 0114 | Flatten Binary Tree to Linked List | Medium | Top_100_Liked_Questions, Depth_First_Search, Tree, Binary_Tree, Stack, Linked_List, Udemy_Linked_List, Big_O_Time_O(N)_Space_O(N) | 47 | 100.00 |
| 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, Big_O_Time_O(N)_Space_O(N) | 71 | 91.78 |
| 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, Big_O_Time_O(N)_Space_O(H) | 55 | 96.72 |
| 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, Big_O_Time_O(N)_Space_O(N) | 66 | 76.43 |
| 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, Big_O_Time_O(N)_Space_O(log(N)) | 58 | 91.34 |
| 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, Big_O_Time_O(N)_Space_O(log(N)) | 68 | 70.23 |
| 0096 | Unique Binary Search Trees | Medium | Top_100_Liked_Questions, Dynamic_Programming, Math, Tree, Binary_Tree, Binary_Search_Tree, Dynamic_Programming_I_Day_11, Big_O_Time_O(n)_Space_O(1) | 57 | 61.54 |
| 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, Big_O_Time_O(n)_Space_O(n) | 56 | 84.00 |
| 0084 | Largest Rectangle in Histogram | Hard | Top_100_Liked_Questions, Top_Interview_Questions, Array, Stack, Monotonic_Stack, Big_O_Time_O(n_log_n)_Space_O(log_n) | 197 | 98.25 |
| 0079 | Word Search | Medium | Top_100_Liked_Questions, Top_Interview_Questions, Array, Matrix, Backtracking, Algorithm_II_Day_11_Recursion_Backtracking, Big_O_Time_O(4^(m*n))_Space_O(m*n) | 56 | 100.00 |
| 0078 | Subsets | Medium | Top_100_Liked_Questions, Top_Interview_Questions, Array, Bit_Manipulation, Backtracking, Algorithm_II_Day_9_Recursion_Backtracking, Udemy_Backtracking/Recursion, Big_O_Time_O(2^n)_Space_O(n*2^n) | 63 | 70.43 |
| 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, Big_O_Time_O(s.length())_Space_O(1) | 175 | 93.33 |
| 0075 | Sort Colors | Medium | Top_100_Liked_Questions, Top_Interview_Questions, Array, Sorting, Two_Pointers, Data_Structure_II_Day_2_Array, Udemy_Arrays, Big_O_Time_O(n)_Space_O(1) | 54 | 88.46 |
| 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, Big_O_Time_O(endRow+endCol)_Space_O(1) | 50 | 97.83 |
| 0073 | Set Matrix Zeroes | Medium | Top_100_Liked_Questions, Top_Interview_Questions, Array, Hash_Table, Matrix, Udemy_2D_Arrays/Matrix, Big_O_Time_O(m*n)_Space_O(1) | 59 | 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, Big_O_Time_O(n^2)_Space_O(n2) | 139 | 73.91 |
| 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, Big_O_Time_O(n)_Space_O(n) | 48 | 96.01 |
| 0064 | Minimum Path Sum | Medium | Top_100_Liked_Questions, Array, Dynamic_Programming, Matrix, Dynamic_Programming_I_Day_16, Udemy_Dynamic_Programming, Big_O_Time_O(m*n)_Space_O(m*n) | 78 | 52.50 |
| 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, Big_O_Time_O(m*n)_Space_O(m*n) | 50 | 91.92 |
| 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, Big_O_Time_O(n_log_n)_Space_O(n) | 103 | 74.70 |
| 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, Big_O_Time_O(n)_Space_O(1) | 88 | 95.88 |
| 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, Big_O_Time_O(n)_Space_O(1) | 125 | 81.22 |
| 0051 | N-Queens | Hard | Top_100_Liked_Questions, Array, Backtracking, Big_O_Time_O(N!)_Space_O(N) | 82 | 88.89 |
| 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, Big_O_Time_O(n*k_log_k)_Space_O(n) | 154 | 83.69 |
| 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, Big_O_Time_O(n^2)_Space_O(1) | 50 | 93.64 |
| 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, Big_O_Time_O(n*n!)_Space_O(n+n!) | 62 | 89.60 |
| 0045 | Jump Game II | Medium | Top_100_Liked_Questions, Array, Dynamic_Programming, Greedy, Algorithm_II_Day_13_Dynamic_Programming, Dynamic_Programming_I_Day_4, Big_O_Time_O(n)_Space_O(1) | 68 | 75.23 |
| 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, Big_O_Time_O(n)_Space_O(1) | 69 | 80.74 |
| 0041 | First Missing Positive | Hard | Top_100_Liked_Questions, Top_Interview_Questions, Array, Hash_Table, Udemy_Arrays, Big_O_Time_O(n)_Space_O(n) | 130 | 65.63 |
| 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, Big_O_Time_O(2^n)_Space_O(n+2^n) | 79 | 74.84 |
| 0035 | Search Insert Position | Easy | Top_100_Liked_Questions, Array, Binary_Search, Algorithm_I_Day_1_Binary_Search, Binary_Search_I_Day_2, Big_O_Time_O(log_n)_Space_O(1) | 48 | 97.37 |
| 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, Big_O_Time_O(log_n)_Space_O(1) | 60 | 77.52 |
| 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, Big_O_Time_O(log_n)_Space_O(1) | 59 | 74.85 |
| 0032 | Longest Valid Parentheses | Hard | Top_100_Liked_Questions, String, Dynamic_Programming, Stack, Big_O_Time_O(n)_Space_O(1) | 73 | 82.61 |
| 0031 | Next Permutation | Medium | Top_100_Liked_Questions, Array, Two_Pointers, Big_O_Time_O(n)_Space_O(1) | 58 | 82.76 |
| 0025 | Reverse Nodes in k-Group | Hard | Top_100_Liked_Questions, Linked_List, Recursion, Data_Structure_II_Day_13_Linked_List, Udemy_Linked_List, Big_O_Time_O(n)_Space_O(k) | 62 | 91.67 |
| 0024 | Swap Nodes in Pairs | Medium | Top_100_Liked_Questions, Linked_List, Recursion, Data_Structure_II_Day_12_Linked_List, Udemy_Linked_List, Big_O_Time_O(n)_Space_O(1) | 59 | 76.00 |
| 0023 | Merge k Sorted Lists | Hard | Top_100_Liked_Questions, Top_Interview_Questions, Heap_Priority_Queue, Linked_List, Divide_and_Conquer, Merge_Sort, Big_O_Time_O(k*n*log(k))_Space_O(log(k)) | 76 | 87.95 |
| 0022 | Generate Parentheses | Medium | Top_100_Liked_Questions, Top_Interview_Questions, String, Dynamic_Programming, Backtracking, Algorithm_II_Day_11_Recursion_Backtracking, Udemy_Backtracking/Recursion, Big_O_Time_O(2^n)_Space_O(n) | 43 | 100.00 |
| 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, Big_O_Time_O(m+n)_Space_O(m+n) | 66 | 59.01 |
| 0020 | Valid Parentheses | Easy | Top_100_Liked_Questions, Top_Interview_Questions, String, Stack, Data_Structure_I_Day_9_Stack_Queue, Udemy_Strings, Big_O_Time_O(n)_Space_O(n) | 53 | 90.52 |
| 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, Big_O_Time_O(L)_Space_O(L) | 51 | 95.27 |
| 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, Big_O_Time_O(4^n)_Space_O(n) | 49 | 93.94 |
| 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, Big_O_Time_O(n*log(n))_Space_O(n^2) | 659 | 83.74 |
| 0011 | Container With Most Water | Medium | Top_100_Liked_Questions, Top_Interview_Questions, Array, Greedy, Two_Pointers, Algorithm_II_Day_4_Two_Pointers, Big_O_Time_O(n)_Space_O(1) | 114 | 95.98 |
| 0010 | Regular Expression Matching | Hard | Top_100_Liked_Questions, Top_Interview_Questions, String, Dynamic_Programming, Recursion, Udemy_Dynamic_Programming, Big_O_Time_O(m*n)_Space_O(m*n) | 66 | 94.44 |
| 0009 | Palindrome Number | Easy | Math, Udemy_Integers | 83 | 74.19 |
| 0008 | String to Integer (atoi) | Medium | Top_Interview_Questions, String | 67 | 67.26 |
| 0007 | Reverse Integer | Medium | Top_Interview_Questions, Math, Udemy_Integers | 58 | 75.27 |
| 0006 | Zigzag Conversion | Medium | String | 77 | 100.00 |
| 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, Big_O_Time_O(n)_Space_O(n) | 117 | 98.63 |
| 0004 | Median of Two Sorted Arrays | Hard | Top_100_Liked_Questions, Top_Interview_Questions, Array, Binary_Search, Divide_and_Conquer, Big_O_Time_O(log(min(N,M)))_Space_O(1) | 64 | 93.81 |
| 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, Big_O_Time_O(n)_Space_O(1) | 94 | 85.62 |
| 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, Big_O_Time_O(max(N,M))_Space_O(max(N,M)) | 68 | 97.48 |
| 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, Big_O_Time_O(n)_Space_O(n) | 57 | 89.38 |
Your ideas/fixes/algorithms are more than welcome!
- Fork this repo
- Clone your forked repo (
git clone https://github.com/YOUR_GITHUB_USERNAME/LeetCode-in-Ruby.git) onto your local machine cdinto your cloned directory, create your feature branch (git checkout -b my-awesome-fix)git addyour desired changes to this repo- Commit your changes (
git commit -m 'Added some awesome features/fixes') - Push to the branch (
git push origin my-awesome-feature) - Open your forked repo on Github website, create a new Pull Request to this repo!