P1090 [NOIP2004 提高组] 合并果子 / [USACO06NOV] Fence Repair G

例题

• 思路：动态的获取队列中最小的两个 然后加在一起呗——要不每次都搬多的得累死

优先队列！

STL里的优先队列 : priority_queue

• 长什么样呢？

priority_queue<int>q;

//从小到大   小根堆
priority_queue<int,vector<int>,greater<int> >q;

//从大到小   大根堆
priority_queue<int,vector<int>,less<int> >q;

#include<bits/stdc++.h>
#define int long long
#define endl '\n'
#define INF 0x3f3f3f3f
using namespace std;
 
const int N = 100010;
int n, x,num,ans;
signed main(){
	std::ios::sync_with_stdio(false);
	cin.tie(0);
	cout.tie(0);
	priority_queue<int, vector<int>,greater<int>> pq;
	cin>>n;
	while(n--){
		cin>>num;
		pq.push(num);
	}
	while(pq.size()>1){
		int a = pq.top();
		pq.pop();
		int b = pq.top();
		pq.pop();
		pq.push(a+b);
		ans =ans+ a+b;
		
	}
	cout<<ans;
}