| # | title | topic | type | difficulty |
|---|---|---|---|---|
| 1 | Two Sum in one pass | Interview Classics | Coding | Medium |
| 2 | LRU cache with O(1) operations | Interview Classics | Coding | Hard |
| 3 | Build an EventEmitter | Interview Classics | Coding | Hard |
| 4 | Balanced brackets with a stack | Interview Classics | Coding | Medium |
| 5 | Longest substring without repeats (sliding window) |
| Interview Classics |
| Coding |
| Hard |
| 6 | Flatten an object to dot-paths (and holes beware) | Interview Classics | Coding | Hard |
| 7 | Trapping rain water (two pointers) | Interview Classics | Coding | Hard |
| 8 | Edit distance (Levenshtein, full DP) | Interview Classics | Coding | Hard |
| 9 | deepClone that preserves cycles | Interview Classics | Coding | Hard |
| 10 | All permutations, in order | Interview Classics | Coding | Hard |
| 11 | Reverse a string | Interview Classics | Coding | Easy |
| 12 | Palindrome check | Interview Classics | Coding | Easy |