条件审判题，条件计算

#include <iostream>
using namespace std;

int func(int x)
{
    if (x <= 5)
        return (x + 1) * x / 2;
    if (5 < x && x <= 10)
        return 100 - (x + 1) * x / 2;
    if (x > 10)
        return x * x;
}

int main()
{
    int a = 0;
    cin >> a;
    cout << func(a);
    return 0;
}