你看我主函数里哪个开了ll（

#include <iostream>
#include <cstdio>
#define int long long
using namespace std;
bool check(int x, int y){
	return x * y >= -2147483648 && x * y <= 2147483647;
}
signed main(){
	int n1, m1, n2, m2;
	cin >> n1 >> m1 >> n2 >> m2;
	if(check(n1, n2) && check(n1, m2) && check(m1, n2) && check(m1, m2)) cout << "int";
	else cout << "long long int";

	return 0;
}

时间复杂度：$O(1)$