优先队列

#include <iostream>
#include <queue>

using namespace std;

int main()
{
    priority_queue < int, vector<int>, greater<int> > q;

    int n;

    cin >> n;
    for(int i = 0;i < n;i++) 
    {
        int x;
        cin >> x;
        q.push(x);
    }

    int res = 0;
    while(q.size() != 1)
    {
        int a = 0;
        a += q.top();
        q.pop();

        a += q.top();
        q.pop();

        res += a ;
        q.push(a);
    }

    cout << res << endl;
    return 0;
}