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| Error Type | Frequency |
| Forget updating or mistakenly changed variable (like reused) in loop | 35 |
| If condition wrong or forgotten | 31 |
| Index & offset target wrong | 28 |
| Wrong variable name or messed up with local variables or operators | 24 |
| Index out of range | 24 |
| Not fully read or understand the problem | 23 |
| Mistakenly treat index with value or incorrectly assigned local var | 17 |
| Forget +/- to index or advance the pointer | 14 |
| Forget empty input case or shortcut case or out of range case | 10 |
| Loop or recursion condition not satisfied unexpectly | 8 |
| Python indentation or syntax wrong! | 8 |
| Edge case not considered | 7 |
| Recursion termination condition wrong or forgotten | 4 |
| Forget to init state before loop | 4 |
| Should use object's field or method but used object itself | 3 |
| Bit operator wrongful usage | 3 |
| Double execution | 2 |
| Forget to update state machine state, for example, counter | 2 |
| Local variable not initialized | 1 |
| Forget to break or continue in loop | 1 |
| Range lower bound not correct as processed | 1 |
| Forget to check container when try to use item from it | 1 |
| Items in collection changed unexpectly | 1 |
| Char to Int forget to convert | 1 |
| [] to String wrong conversion | 1 |
| Python multiple assignment order | 1 |
| Forget to add inheritance | 1 |