| ID | Title | Difficulty |
|---|---|---|
| 1 | Two Sum | easy |
| 2 | Add Two Numbers | medium |
| 13 | Roman to Integer | easy |
| 14 | Longest Common Prefix | easy |
| 21 | Merge Two Sorted Lists | easy |
| 43 | Multiply Strings | medium |
| 54 | Spiral Matrix | medium |
| 112 | Path Sum | easy |
| 202 | Happy Number | easy |
| 205 | Isomorphic Strings | easy |
| 206 | Reverse Linked List | easy |
| 234 | Palindrome Linked List | easy |
| 328 | Odd Even Linked List | medium |
| 387 | First Unique Character in a String | easy |
| 392 | Is Subsequence | easy |
| 557 | Reverse Words in a String III | easy |
| 718 | Maximum Length of Repeated Subarray | medium |
| 724 | Find Pivot Index | easy |
| 804 | Unique Morse Code Words | easy |
| 981 | Time Based Key-Value Store | medium |
| 1338 | Reduce Array Size to The Half | medium |
| 1480 | Running Sum of 1d Array | easy |
| 1680 | Concatenation of Consecutive Binary Numbers | medium |
| 1706 | Where Will the Ball Fall | medium |