```cpp
cin >> n >> k;
s='.';//注意这行
for (int i = 1; i <= n; i++)
{
cin >> s[i];
}
```
就可以运行了
by wangbinfeng @ 2024-04-27 10:27:02
我不怎么用STL,但是我猜是 `string` 查字符串长度是从 0 开始搜,然后 `s[0]='\0'`,算出了`s.length==0`
然后 `substr` 函数主体运行前要先检查字符串长度是否合法,检查到不合法就 `throw` 了
@[zhaojinhong](/user/907408) 看到的话回复下qwq
by wangbinfeng @ 2024-04-27 10:31:30
@[wangbinfeng](/user/387009) qwq
by zhaojinhong @ 2024-04-27 11:27:38