Codeforces 4538 （状态压缩dp）Little Pony and Harmony Chest

Little Pony and Harmony Chest

经典状态压缩dp

#include <cstdio>
#include <cstring>
#include <cstdlib>
#include <iostream>
#define min(x,y) (x>y?y:x)
using namespace std;
int factor[],all,n,a[],b[][<<],pre[][<<],s1,s0,f[][<<],ansk;
bool pd[];
void print(int i,int k)
{
    if(i==) return;
    print(i-,pre[i][k]);
    if(i==n) printf("%d",b[i][k]); else printf("%d ",b[i][k]);
    return;
}
int main()
{
    pd[]=;
    for(int i=; i<=; i++)
    if(!pd[i]){
        factor[++all]=i;
        for(int j=; i*j<=; j++)
            pd[i*j]=;
    }
    scanf("%d",&n);
    for(int i=; i<=n; i++)
        scanf("%d",&a[i]);
    memset(f,,sizeof(f));
    for(int i=; i<=(<<)-; i++)
        f[][i]=;

    int ans=;
    for(int i=; i<=n; i++)
        for(int j=; j<=; j++)
        {
            s1=(<<)-;
            for(int k=; k<; k++)
                if(j%factor[k]==) s1=s1^(<<(k-));
            s0=s1^((<<)-);
            for(int k=; k<=(<<)-; k++)
            {
                int p0=k&s1,p1=(k&s1)+s0;
                if(f[i][p1]>f[i-][p0]+abs(a[i]-j))
                {
                    f[i][p1]=f[i-][p0]+abs(a[i]-j);
                    b[i][p1]=j;
                    pre[i][p1]=p0;
                }
                if(i==n&&ans>f[n][p1])
                {
                    ans=f[n][p1];
                    ansk=p1;
                }
            }
        }
    print(n,ansk);
    return ;
}