- E indicate Easy, M indicate Medium and H indicate Hard.
- "+" means need to redo.
- "-" means failed to solve.
- "?" means cannot understand the purpose of this problem.
- "^" means needing a faster solution.
- Arrays
- Recursion and Dynamic Programming
- Fast and Slow Pointers
- Stack and Queue
- Search and Sorting
- Trees and Graphs
index | date | notes |
---|---|---|
212.Contains Duplicate (E) | 2021-06-26 | |
268.Missing Number (E) | 2021-06-27 | + |
448.Find All Numbers Disappeared in an Array (E) | 2021-06-27 | run time error |
136. Single Number (E) | 2021-06-28 | |
344. Reverse String (E) | 2021-06-29 | in-place |
541. Reverse String II (E) | 2021-07-01 | + |
566. Reshape the Matrix (E) | 2021-07-11 | ^ |
66. Plus One (E) | 2021-07-14 | |
268. Missing Number (E) | 2021-07-15 | |
242. Valid Anagram (E) | 2021-07-15 | |
384. Shuffle an Array (M) | 2021-07-20 | ++ deep copy of list |
7. Reverse Integer (E) | 2021-07-21 | |
11. Container With Most Water (M) | 2021-07-25 | |
13. Roman to Integer (E) | 2021-07-27 | |
3. Longest Substring Without Repeating Characters (M) | 2021-07-28 | |
409. Longest Palindrome (E) | 2021-07-31 | |
383. Ransom Note (E) | 2021-08-02 | |
5. Longest Palindromic Substring (M) | 2021-08-05 | + |
169. Majority Element (E) | 2021-08-06 | + |
8. String to Integer (atoi) (M) | 2021-08-07 | + |
9. Palindrome Number | 2021-08-07 | |
12. Integer to Roman (M) | 2021-08-09 | |
14. Longest Common Prefix (E) | 2021-08-09 | |
26. Remove Duplicates from Sorted Array (E) | 2021-08-10 | |
16. 3Sum Closest(M) | 2021-08-11 | + |
35. Search Insert Position (E) | 2021-08-18 | |
48. Rotate Image (M) | 2021-08-18 | + |
43. Multiply Strings (M) | 2021-08-21 | |
49. Group Anagrams (M) | 2021-08-29 | |
36. Valid Sudoku (M) | 2021-08-30 | |
848. Shifting Letters (M) | 2021-09-08 | ord() and chr() |
56. Merge Intervals (M) | 2021-10-06 | |
index | date | notes |
---|---|---|
70. Climbing Stairs (E) | 2021-06-28 | |
121. Best Time to Buy and Sell Stock (E) | 2021-06-28 | + |
53. Maximum Subarray (E) | 2021-07-05 | - |
303. Range Sum Query - Immutable (E) | 2021-07-05 | ? |
46. Permutations (M) | 2021-07-06 | |
322. Coin Change (M) | 2021-07-08 | ++ |
338. Counting_Bits (E)) | 2021-07-08 | bin operation |
198. House Robber (M) | 2021-07-12 | + |
118. Pascal's Triangle (E) | 2021-07-28 | |
17. Letter Combinations of a Phone Number (M) | 2021-08-15 | Backtrack |
45. Jump Game II (M) | 2021-08-21 | |
55. Jump Game (M) | 2021-08-21 | |
198. House Robber (E) | 2021-09-11 | |
1911. Maximum Alternating Subsequence Sum (M) | 2021-09-12 | + |
300. Longest Increasing Subsequence (M) | 2021-09-12 | + |
416. Partition Equal Subset Sum (M) | 2021-09-12 | + |
213. House Robber II (M) | 2021-09-26 | |
index | date | notes |
---|---|---|
141. Linked List Cycle (E) | 2021-07-09 | |
876. Middle of the Linked List (E) | 2021-07-09 | |
206. Reverse Linked List (E) | 2021-07-10 | + |
19. Remove Nth Node From End of List (M) | 2021-07-11 | |
234. Palindrome Linked List (E) | 2021-07-12 | |
2. Add Two Numbers (M) | 2021-07-19 | |
82. Remove Duplicates from Sorted List II (M) | 2021-07-27 | + |
27. Remove Element (E) | 2021-08-01 | |
24. Swap Nodes in Pairs (M) | 2021-08-16 | ++ |
index | date | notes |
---|---|---|
20. Valid Parentheses (E) | 2021-07-16 | |
232. Implement Queue using Stacks (E) | 2021-07-18 | |
155. Min Stack (E) | 2021-07-27 | ^ |
641. Design Circular Deque (M) | 2021-08-01 | |
225. Implement Stack using Queues (E) | 2021-08-03 | |
index | date | notes |
---|---|---|
704. Binary Search (E) | 2021-07-23 | |
169. Majority Element (E) | 2021-07-29 | + |
15. 3Sum (M) | 2021-08-02 | + |
69. Sqrt(x) (E) | 2021-08-03 | + |
31. Next Permutation (M) | 2021-08-17 | ++ |
33. Search in Rotated Sorted Array (M) | 2021-08-26 | + |
34. Find First and Last Position of Element in Sorted Array (M) | 2021-08-26 | |
index | date | notes |
---|---|---|
98. Validate Binary Search Tree (M) | 2021-08-23 | + |
100. Same Tree (E) | 2021-08-23 | |
94. Binary Tree Inorder Traversal (E) | 2021-08-23 | |
96. Unique Binary Search Trees (M) | 2021-09-02 | |
95. Unique Binary Search Trees II (M) | 2021-09-07 | ++ |
987. Vertical Order Traversal of a Binary Tree (H) | 2021-10-08 | |