改成n-1后下面那个圈外循环
```cpp
a[ans].dir==1
```
by L_cm_C5H6 @ 2022-03-26 23:49:41
@[L_cm_C5H6](/user/429699) 感谢回复！顺带问一下，为什么循环必须是0~n-1才行
by Simon_Lu @ 2022-03-27 13:30:22
@[Simon_Lu](/user/222555) 单纯%n不是只能得到0到n-1么...ans=1的话应该对ans操作%n后都要+1吧？
by L_cm_C5H6 @ 2022-03-27 14:54:58
@[L_cm_C5H6](/user/429699) 明白了，谢谢！
by Simon_Lu @ 2022-03-27 22:41:19