| 文件序号 | iter->second | res = (x % 12) + 1 | 新 iter->second |
|---|---|---|---|
| 1 | 0 | 1 | (0 + 4) % 12 = 4 |
| 2 | 4 | 5 | (4 + 4) % 12 = 8 |
| 3 | 8 | 9 | (8 + 4) % 12 = 0 |
| 4 | 0 | 1 | 4 |
| 5 | 4 | 5 | 8 |
| 6 | 8 | 9 | 0 |
结果是：
起始 chain 序列：1 → 5 → 9 → 1 → 5 → 9 → ...
| 文件序号 | iter->second | res = (x % 12) + 1 | 新 iter->second |
|---|---|---|---|
| 1 | 0 | 1 | (0 + 4) % 12 = 4 |
| 2 | 4 | 5 | (4 + 4) % 12 = 8 |
| 3 | 8 | 9 | (8 + 4) % 12 = 0 |
| 4 | 0 | 1 | 4 |
| 5 | 4 | 5 | 8 |
| 6 | 8 | 9 | 0 |
结果是：
起始 chain 序列：1 → 5 → 9 → 1 → 5 → 9 → ...