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 | 2306 / 2327 | 800 | |
| ABC string | 1984 / 2015 | 800 | |
| Subset sum | 1805 / 1972 | 800 | |
| Subset | 1667 / 1733 | 800 | |
| Permutations | 1351 / 1405 | 800 | |
| Group division | 918 / 994 | 800 | |
| Knight's tour | 863 / 977 | 800 | |
| N-queens problem | 865 / 890 | 800 | |
| Maximum path | 908 / 917 | 800 | |
| Knapsack | 845 / 937 | 800 | |
| Build array | 550 / 578 | 800 | |
| Sudoku | 539 / 572 | 800 | |
| Minesweeper | 257 / 367 | 800 | |
| Travelling Salesman Problem | 491 / 516 | 800 | |
| Word search | 423 / 438 | 800 |