Backtracking
Frequency: 9/10
Many people underestimate this very important technique. Backtracking may be needed for solving the first subtask in OI contest. Moreover, backtracking is a powerful tool for debugging.Resources
Problems
| Binary string | 1613 / 1621 | 800 | |
| ABC string | 1368 / 1387 | 800 | |
| Subset sum | 1283 / 1405 | 800 | |
| Subset | 1209 / 1252 | 800 | |
| Permutations | 945 / 990 | 800 | |
| Group division | 645 / 706 | 800 | |
| Knight's tour | 603 / 695 | 800 | |
| N-queens problem | 628 / 651 | 800 | |
| Maximum path | 647 / 655 | 800 | |
| Knapsack | 612 / 689 | 800 | |
| Build array | 409 / 426 | 800 | |
| Sudoku | 404 / 429 | 800 | |
| Minesweeper | 189 / 265 | 800 | |
| Travelling Salesman Problem | 372 / 388 | 800 | |
| Word search | 322 / 337 | 800 |