NYOJ 55 （优先队列）

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 1 #include<iostream>
 2 #include<cstdio>
 3 #include<queue>
 4 using namespace std;
 5 priority_queue <int ,vector<int>,greater<int> > q;
 6 int main()
 7 {
 8   int t,n,x,y,sum;
 9   int i;
10   scanf("%d",&t);
11   while(t--)
12    {
13      while(!q.empty())q.pop();
14      sum=0;
15      scanf("%d",&n);
16      for(i=0;i<n;++i)
17       {
18         scanf("%d",&x);
19         q.push(x);
20       }
21      while(!q.empty())
22       {
23         x=q.top();//注意是q.top() 
24         q.pop();
25         if(q.empty())break;
26         y=q.top();
27         q.pop();
28         sum+=x+y;
29         q.push(x+y);
30       }
31       printf("%d\n",sum);
32    }
33   system("pause");
34   return 0;
35 }