POJ

题目链接：https://vjudge.net/problem/POJ-3087

模拟洗牌的过程

#include<iostream>
#include<algorithm>
#include<string>
#include<cstring>
#include<cstdio>
#include<cmath>
#include<stack>
#include<queue>
#include<map>

using namespace std;
typedef long long ll;
const int maxn = 5e4 + 5;
const int INF = 0x3f3f3f3f;

map<string, bool>mp;

int main()
{
    int t;
    cin >> t;
    for (int k = 1; k <= t; k++) {
        int len;
        cin >> len;
        string s1, s2, str, tmp;
        cin >> s1 >> s2 >> str;
        int ans = 0, flag = 1;
        mp.clear();
        while (flag) {
            tmp = "";
            for (int i = 0; i < len; i++) {
                tmp += s2[i];
                tmp += s1[i];
            }
            ans++;
            if (tmp == str) {
                cout << k << " " << ans << endl;
                break;
            }
            s1 = tmp.substr(0, len);
            s2 = tmp.substr(len);
            if (mp[tmp]) {
                flag = 0;
                break;
            }
            mp[tmp] = true;
        }
        if (flag == 0) {
            cout << k << " " << -1 << endl;
        }
    }
    return 0;
}