看注释

#include <iostream>
#include <cmath>
#include <climits>
using namespace std;
int main()
{
    int x1, y1, x2, y2;
    cin >> x1 >> y1 >> x2 >> y2;
    long long max1, max2;
    // 获取绝对值， 排除负数影响
    x1 = abs(x1);
    x2 = abs(x2);
    y1 = abs(y1);
    y2 = abs(y2);

    // 获取两个边界最大值
    max1 = max(x1, y1);
    max2 = max(x2, y2);

    // 若有最大值为零，乘积同样为零
    if (max1 == 0 || max2 == 0)
    {
        cout << "int";
        return 0;
    }

    // 若有最大值大于int范围最大值
    if (max1 > INT_MAX || max2 > INT_MAX)
    {
        cout << "long long";
        return 0;
    }

    // 有一个最大值大于ing范围最大值与另一个最大值的商
    if (INT_MAX / max1 < max2 || INT_MAX / max2 < max1)
    {
        cout << "long long";
        return 0;
    }

    cout << "int";
    return 0;
}