用优先队列就是方便

#include <queue>
#include <iostream>
#include <algorithm>
using namespace std;
int main ()
{
priority_queue<int,vector<int>,greater<int> > pq;//小根堆
int n,x,sum=0;
cin>>n;
for(int i=0;i<n;i++)
{
cin>>x;
pq.push(x);
}
x=0;
while(pq.size()>1)
{
x+=pq.top();pq.pop();
x+=pq.top();pq.pop();
sum+=x;pq.push(x);
x=0;
}
cout<<sum;
return 0;
}