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 | 1531 / 1539 | 800 | |
| ABC string | 1297 / 1316 | 800 | |
| Subset sum | 1221 / 1348 | 800 | |
| Subset | 1157 / 1201 | 800 | |
| Permutations | 896 / 939 | 800 | |
| Group division | 614 / 674 | 800 | |
| Knight's tour | 573 / 661 | 800 | |
| N-queens problem | 596 / 618 | 800 | |
| Maximum path | 619 / 627 | 800 | |
| Knapsack | 582 / 657 | 800 | |
| Build array | 389 / 406 | 800 | |
| Sudoku | 384 / 409 | 800 | |
| Minesweeper | 174 / 246 | 800 | |
| Travelling Salesman Problem | 354 / 369 | 800 | |
| Word search | 305 / 319 | 800 |