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 | 964 / 969 | 800 | |
| ABC string | 792 / 812 | 800 | |
| Subset sum | 780 / 865 | 800 | |
| Subset | 751 / 788 | 800 | |
| Permutations | 527 / 563 | 800 | |
| Group division | 354 / 395 | 800 | |
| Knight's tour | 361 / 421 | 800 | |
| N-queens problem | 373 / 391 | 800 | |
| Maximum path | 380 / 388 | 800 | |
| Knapsack | 345 / 411 | 800 | |
| Build array | 229 / 240 | 800 | |
| Sudoku | 223 / 245 | 800 | |
| Minesweeper | 87 / 132 | 800 | |
| Travelling Salesman Problem | 229 / 241 | 800 | |
| Word search | 175 / 186 | 800 |