| # | Title | Solution | Difficulty | Tag | Familiarity |
|---|---|---|---|---|---|
| 1 | Two Sum | Java | Easy | #Array #HashTable | * |
| 2 | Add Two Numbers | Java | Easy | #LinkedList | * |
| 15 | 3Sum | Java | Medium | #Array #Sort #TwoPointers | * |
| 16 | 3Sum Closest | Java | Medium | #Array #Sort #TwoPointers | |
| 20 | Valid Parentheses | Java | Easy | #Stack #状态机 | * |
| 21 | Merge Two Sorted Lists | Java | Easy | #LinkedList | * |
| 71 | Simplify Path | Java | Medium | #Stack #状态机 | * |
| 235 | Lowest Common Ancestor of a Binary Search Tree | Java | Easy | #Tree | * |
| 236 | Lowest Common Ancestor of a Binary Tree | Java | Easy | #Tree #Dfs | |
| 237 | Delete Node in a Linked List | Java | Easy | #LinkedList | * |
| 328 | Odd Even Linked List | Java | Easy | #LinkedList | * |
| 343 | Integer Break | Java | Easy | #DP #数学 | * |
| 344 | Reverse String | Java | Easy | #String | * |
| 345 | Reverse Vowels of a String | Java | Easy | #String | * |
| 401 | Binary Watch | Java | Easy | #Bit | * |
| 402 | Remove K Digits | Java | Easy | #String #Greedy | |
| 430 | Flatten a Multilevel Doubly Linked List | Java | Medium | #LinkedList #Dfs | * |