题解

#include<bits/stdc++.h>
#define reg register
#define ll long long
#define inf 0x3f3f3f3f
#define null liuyifan_null
#define y1 liuyifan_y1
#define next liuyifan_next
#define data liuyifan_data
using namespace std;
priority_queue<ll>q;//默认为大根堆
ll n,x,ans;
int main()
{
    scanf("%lld",&n);
    for(reg int i=1;i<=n;i++)
	{
        scanf("%lld",&x);
        q.push(x);//插入堆
        if(q.top()>x)
		{
            ans+=q.top()-x;//top:堆顶的值
            q.pop();//弹出堆顶
            q.push(x);
        }
    }
    printf("%lld",ans);
    return 0;
}