输入挂了
```cpp
while(1) {
cin >> x >> y;
if(x == -1 && y == -1) {
break;
}
add(x, y, 1);
add(y, x, 0);
}
```
by Skicyer @ 2023-09-07 14:14:49
@[Skicyer](/user/913131) 已A， 多谢。
by Dawn_chen @ 2023-09-07 20:52:06