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 | 1300 / 1308 | 800 | |
| ABC string | 1085 / 1104 | 800 | |
| Subset sum | 1031 / 1147 | 800 | |
| Subset | 977 / 1018 | 800 | |
| Permutations | 728 / 768 | 800 | |
| Group division | 495 / 555 | 800 | |
| Knight's tour | 476 / 558 | 800 | |
| N-queens problem | 495 / 515 | 800 | |
| Maximum path | 515 / 523 | 800 | |
| Knapsack | 474 / 551 | 800 | |
| Build array | 315 / 330 | 800 | |
| Sudoku | 309 / 332 | 800 | |
| Minesweeper | 131 / 190 | 800 | |
| Travelling Salesman Problem | 297 / 310 | 800 | |
| Word search | 240 / 252 | 800 |