POJ 3253 Fence Repair(哈夫曼树）

#include <iostream>
#include <cstdio>
#include <queue>
#include <vector>
#include <algorithm>
using namespace std;
int main()
{
int n,i;
__int64 sum,a,b;
scanf("%d",&n);
priority_queue< __int64 ,vector<__int64>,greater<__int64> > q;
for(i = 1;i <= n;i ++)
{
scanf("%I64d",&a);
q.push(a);
}
sum = 0;
for(i = 1;i <= n-1;i ++)
{
a = q.top();
q.pop();
b = q.top();
q.pop();
sum += a+b;
q.push(a+b);
}
printf("%I64d\n",sum);
return 0;
}