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 |
| 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 |
| 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 |
| 0045 | Jump Game II | Medium | Top_100_Liked_Questions, Array, Dynamic_Programming, Greedy, Big_O_Time_O(n)_Space_O(1) | 68 | 75.23 |
| 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 |
| 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 |
| 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 |
| 0045 | Jump Game II | Medium | Top_100_Liked_Questions, Array, Dynamic_Programming, Greedy, 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, Big_O_Time_O(n)_Space_O(1) | 69 | 80.74 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| # | Title | Difficulty | Tag | Time, ms | Time, % |
|---|---|---|---|---|---|
| 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!