Top 10 problems · patterns · complexity reference · live-coding rules
O(log n).
n log n > n (n log n grows faster). Aim to beat n² when possible — but a correct n² beats a broken n.
| Structure | Access | Search | Insert | Delete |
|---|---|---|---|---|
| Array / List | O(1) | O(n) | O(n) | O(n) |
| Hash map / dict | — | O(1) | O(1) | O(1) |
| Hash set | — | O(1) | O(1) | O(1) |
| Stack / Queue | O(n) | O(n) | O(1) | O(1) |
| Linked list | O(n) | O(n) | O(1) | O(1) |
| Binary heap | O(1) min | O(n) | O(log n) | O(log n) |
| BST (balanced) | O(log n) | O(log n) | O(log n) | O(log n) |
| Sorted array + binary search | O(1) | O(log n) | O(n) | O(n) |