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 | 1069 / 1074 | 800 | |
| ABC string | 889 / 907 | 800 | |
| Subset sum | 870 / 956 | 800 | |
| Subset | 829 / 866 | 800 | |
| Permutations | 597 / 632 | 800 | |
| Group division | 410 / 459 | 800 | |
| Knight's tour | 410 / 477 | 800 | |
| N-queens problem | 418 / 436 | 800 | |
| Maximum path | 442 / 450 | 800 | |
| Knapsack | 396 / 465 | 800 | |
| Build array | 264 / 277 | 800 | |
| Sudoku | 251 / 273 | 800 | |
| Minesweeper | 103 / 153 | 800 | |
| Travelling Salesman Problem | 252 / 266 | 800 | |
| Word search | 202 / 214 | 800 |