P1090 [NOIP 2004 提高组] 合并果子

#include <bits/stdc++.h>
using namespace std;

int main() {
    ios::sync_with_stdio(false);
    cin.tie(nullptr);

    int n;
    cin >> n;

    // 小根堆：随时能取出当前最小的两堆
    priority_queue<int, vector<int>, greater<int>> heap;
    for (int i = 0; i < n; i++) {
        int a;
        cin >> a;
        heap.push(a);
    }

    long long cost = 0;
    while (heap.size() > 1) {
        int a = heap.top();
        heap.pop();
        int b = heap.top();
        heap.pop();

        int merged = a + b;   // 本次合并消耗的体力
        cost += merged;
        heap.push(merged);
    }

    cout << cost << "\n";
    return 0;
}