3531. 哈夫曼树

思路：用堆模拟哈夫曼树

代码：

#include <iostream>
#include <cstring>
#include <algorithm>
#include <queue>

using namespace std;

int main()
{
    
    priority_queue<int, vector<int>, greater<int>> q;
    int n;
    scanf("%d", &n);
    while(n -- ){
    
        int x;
        scanf("%d", &x);
        q.push(x);
    }
    
    int sum = 0, res = 0;
    while(q.size() > 1){
    
        int a = q.top();
        q.pop();
        int b = q.top();
        q.pop();
        sum = a + b;
        q.push(sum);
        res += sum;
    }
    
    cout << res << endl;
    return 0;
}