poj 1721 CARDS (置换群)

//给出置换了s次后的序列，求原序列
# include <stdio.h>
# include <algorithm>
# include <string.h>
using namespace std;
int main()
{
    int n,s,t,s1,i,cot;
    int a[1010],b[1010],c[1010];
    while(~scanf("%d%d",&n,&s))
    {
        for(i=1; i<=n; i++)
        {
            scanf("%d",&a[i]);
            b[i]=a[i];
            c[i]=a[i];
        }
        cot=0;
        while(1)//求循环节
        {
            cot++;
            for(i=1; i<=n; i++)
                b[i]=c[c[i]];
            for(i=1; i<=n; i++)
            {
                if(a[i]!=b[i])
                    break;
            }
            if(i>n)
                break;
            for(i=1; i<=n; i++)
                c[i]=b[i];
        }
        s%=cot;
        s=cot-s;
        while(s--)
        {
            for(i=1; i<=n; i++)
                b[i]=a[a[i]];
            for(i=1; i<=n; i++)
                a[i]=b[i];
        }
        for(i=1; i<=n; i++)
            printf("%d\n",b[i]);
    }
    return 0;
}

poj 1721 CARDS (置换群)

原文：http://blog.csdn.net/lp_opai/article/details/39010875