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 | 1320 / 1328 | 800 | |
| ABC string | 1100 / 1119 | 800 | |
| Subset sum | 1045 / 1163 | 800 | |
| Subset | 989 / 1032 | 800 | |
| Permutations | 741 / 781 | 800 | |
| Group division | 504 / 564 | 800 | |
| Knight's tour | 482 / 569 | 800 | |
| N-queens problem | 501 / 521 | 800 | |
| Maximum path | 523 / 532 | 800 | |
| Knapsack | 483 / 558 | 800 | |
| Build array | 321 / 336 | 800 | |
| Sudoku | 316 / 339 | 800 | |
| Minesweeper | 132 / 196 | 800 | |
| Travelling Salesman Problem | 300 / 313 | 800 | |
| Word search | 246 / 258 | 800 |