7-29 修理牧场 (25分)--优先队列

#include <iostream>
#include <string>
#include <cstring>
#include <queue>
#include <vector>
using namespace std;
priority_queue<int, vector<int>, greater<int>>q;
int main()
{
    int n;
    int sum_=0;
    cin >> n;
    if(n==1){cout << "0"; return 0;}
    for (int i = 0; i < n; i++)
    {
        int t;
        cin >> t;
        q.push(t);
    }
    while (!q.empty())
    {
        int a = q.top(); q.pop();
        if (!q.empty())
        {
            int b = q.top(); q.pop();
            sum_ += (a + b);
            if(!q.empty())
            q.push(a + b);
        }
        else
            sum_ += a;
    }
    cout << sum_ << endl;
}