POJ3087 Shuffle'm Up

AC代码：

#include <iostream>
#include <cstdio>
#include <cmath>
#include <cstring>
#include <string>
#include <queue>
#include <map>
using namespace std;

map<string,int> ma;
string s1,s2,s3;
int c;

int solve(){
    ma.clear();
    string str;
    int cnt = 0;
    while(1){
        str = "";
        for(int i = 0; i < c; i++){
            str += s2[i];
            str += s1[i];
        }
        cnt++;
        if(ma[str])
            break;
        if(str == s3)
            return cnt;
        ma[str]++;
        s1 = "";s2 = "";
        for(int i = 0; i < c; i++)
            s1 += str[i];
        for(int i = c; i < 2*c; i++)
            s2 += str[i];
    }
    return -1;
}

int main(){
    int T,t = 1;
    scanf("%d",&T);
    while(T--){
        scanf("%d",&c);
        cin>>s1>>s2>>s3;
        printf("%d %d\n",t++,solve());
    }
    return 0;
}