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 | 591 / 593 | 800 | |
| ABC string | 488 / 500 | 800 | |
| Subset sum | 510 / 572 | 800 | |
| Subset | 508 / 541 | 800 | |
| Permutations | 325 / 342 | 800 | |
| Group division | 228 / 253 | 800 | |
| Knight's tour | 251 / 298 | 800 | |
| N-queens problem | 260 / 273 | 800 | |
| Maximum path | 259 / 266 | 800 | |
| Knapsack | 236 / 280 | 800 | |
| Build array | 160 / 168 | 800 | |
| Sudoku | 159 / 177 | 800 | |
| Minesweeper | 52 / 85 | 800 | |
| Travelling Salesman Problem | 162 / 171 | 800 | |
| Word search | 129 / 132 | 800 |