poj3087

简单模拟，每次看当前的牌是否与初始状态相同，若相同则说明进入循环。

#include <iostream>
#include <cstdlib>
#include <cstring>
#include <cstdio>
using namespace std;

#define maxl 205

char s1[maxl], s2[maxl], aim[maxl], st[maxl], s3[maxl];
int l;

int main()
{
    //freopen("t.txt", "r", stdin);
    int t;
    scanf("%d", &t);
    for (int ca = 0; ca < t; ca++)
    {
        scanf("%d", &l);
        scanf("%s", s1);
        scanf("%s", s2);
        scanf("%s", aim);
        strcpy(st, s1);
        strcpy(st + l, s2);
        int ans = 0;
        do
        {
            for (int i = 0; i < l; i++)
            {
                s3[i * 2 + 1] = s1[i];
                s3[i * 2] = s2[i];
            }
            s3[l * 2] = '\0';
            ans++;
            if (strcmp(s3, st) == 0)
            {
                ans = -1;
                break;
            }
            for (int i = 0; i < l; i++)
                s1[i] = s3[i];
            for (int i = 0; i < l; i++)
                s2[i] = s3[i + l];
        }while (strcmp(s3, aim) != 0);
        printf("%d %d\n", ca + 1, ans);
    }
    return 0;
}