BZOJ 1592 DP

思路:f[i][j]表示前i个数 最后一个数是原数列的第j个的 最小值

//By SiriusRen
#include <cstdio>
#include <cstring>
#include <algorithm>
using namespace std;
int n,a[2222],cpy[2222],minn[2222],f[2222][2222],temp[2222],ans=0x7fffffff;
void work(){
    memset(f,0x3f,sizeof(f));
    memset(minn,0,sizeof(minn));
    for(int i=1;i<=n;i++){
        memset(temp,0x3f,sizeof(temp));
        for(int j=1;j<=n;j++){
            f[i][j]=min(minn[j]+abs(cpy[j]-a[i]),f[i][j]);
            if(j==1)temp[j]=f[i][j];
            else temp[j]=min(temp[j-1],f[i][j]);
        }
        for(int j=1;j<=n;j++)minn[j]=temp[j];
    }
    for(int i=1;i<=n;i++)ans=min(ans,f[n][i]);
}
int main(){
    scanf("%d",&n);
    for(int i=1;i<=n;i++)scanf("%d",&a[i]),cpy[i]=a[i];
    sort(cpy+1,cpy+1+n);
    work(),reverse(a+1,a+1+n),work();
    printf("%d
",ans);
}

这里写图片描述

原文地址:https://www.cnblogs.com/SiriusRen/p/6532173.html