开```long long```有时是```Accepted```与```Unaccepted```之间的永恒主题。
```cpp
#include <iostream>
using namespace std;

int x1, x2, y1, y2;
long long xy1, xy2;

int main() {
    cin >> x1 >> x2 >> y1 >> y2;
    xy1 = (long long)x1*y1, xy2 = (long long)x2*y2;
    if (xy1<-2147483648ll || xy2>2147483647) cout << "long long int";
    else cout << "int";
    return 0;
}
```


禁止在 int 乘 int 时不开 long long

A21400.开long long

分治·分治练习生

开long long有时是Accepted与Unaccepted之间的永恒主题。