用优先队列代替堆水过：

#include<bits/stdc++.h>
using namespace std;
long long tmp,n,ans=0;
int main(){
    priority_queue<long long,vector<long long>,greater<long long> > q;
    cin>>n;
    for(int i=1;i<=n;i++){
        cin>>tmp;
        q.push(tmp);
    }
    for(int i=1;i<=n-1;i++){
        int a,b;
        a=q.top();
        q.pop();
        b=q.top();
        q.pop();
        ans+=a+b;
        q.push(a+b);
    }
    cout<<ans;
}