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 | 1290 / 1297 | 800 | |
| ABC string | 1077 / 1095 | 800 | |
| Subset sum | 1022 / 1137 | 800 | |
| Subset | 971 / 1012 | 800 | |
| Permutations | 726 / 765 | 800 | |
| Group division | 492 / 552 | 800 | |
| Knight's tour | 475 / 556 | 800 | |
| N-queens problem | 493 / 513 | 800 | |
| Maximum path | 512 / 520 | 800 | |
| Knapsack | 473 / 549 | 800 | |
| Build array | 313 / 328 | 800 | |
| Sudoku | 306 / 328 | 800 | |
| Minesweeper | 128 / 188 | 800 | |
| Travelling Salesman Problem | 292 / 305 | 800 | |
| Word search | 237 / 249 | 800 |