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 | 817 / 820 | 800 | |
| ABC string | 676 / 691 | 800 | |
| Subset sum | 668 / 743 | 800 | |
| Subset | 641 / 676 | 800 | |
| Permutations | 440 / 468 | 800 | |
| Group division | 304 / 338 | 800 | |
| Knight's tour | 315 / 370 | 800 | |
| N-queens problem | 324 / 340 | 800 | |
| Maximum path | 319 / 325 | 800 | |
| Knapsack | 291 / 349 | 800 | |
| Build array | 202 / 210 | 800 | |
| Sudoku | 194 / 213 | 800 | |
| Minesweeper | 69 / 108 | 800 | |
| Travelling Salesman Problem | 204 / 216 | 800 | |
| Word search | 157 / 163 | 800 |