@[JeffZhao](/user/120017) 我在我自己中间出现了 0 次?
by LongDouble @ 2022-03-09 17:18:36
真正的 hack:
```
ababPPaPP
3
1 3
2 3
2 4
```
输出应该是三个 $1$。
by LongDouble @ 2022-03-09 17:24:25
感谢真正的hack
by chenguoyi @ 2023-01-18 07:32:19