2020 腾讯笔试题——顾客不满意度总和最小

#include 
#include 
#include 
using namespace std;

struct sat
{
    long a;
    long b;
};

bool cmp(sat a, sat b)
{
    return (a.a - a.b) > (b.a - b.b);
}

int main()
{
    long n;
    cin >> n;
    vector a(n);
    long i1, i2;
    for (int i = 0; i < n; ++i)
    {
        cin >> a[i].a >> a[i].b;
    }
    sort(a.begin(), a.end(), cmp);
    long ans = 0;
    for (int i = 1; i <= n; ++i)
    {
        ans += (a[i-1].a * (i-1)) + (a[i-1].b * (n-i));
    }
    cout << ans;
    return 0;
}