HDU 1522 marriage is stable

The question ： Stable marriage matching problem , Board question .

Answer key ： Stable marriage matching
Fortunately, I did this problem , There was something wrong with the previous board ,1435 The data is too weak .

#define _CRT_SECURE_NO_WARNINGS
#include<iostream>
#include<cstdio>
#include<string>
#include<cstring>
#include<algorithm>
#include<queue>
#include<stack>
#include<cmath>
#include<vector>
#include<fstream>
#include<set>
#include<map>
#include<sstream>
#include<iomanip>
#define ll long long
#define pii pair<int, int>
using namespace std;
// Stable marriage matching 
const int maxn = 505;
string str[maxn * 2];
int n;
int boy_love_who[maxn][maxn], girl_love_fir[maxn][maxn];
int boy[maxn], girl[maxn], kth[maxn];
inline void G_S() {
    
    for (int i = 1; i <= n; i++) boy[i] = girl[i] = kth[i] = 0;
    bool flag, no = 0;
    int xx = 1;
    while (true) {
    
        flag = false;
        for (int i = 1; i <= n; i++) {
    
            if (!boy[i]) {
    
                int g = boy_love_who[i][++kth[i]];
                if (kth[i] > n) {
    
                    no = 1;
                    break;
                }
                if (!girl[g]) {
    
                    girl[g] = i;
                    boy[i] = g;
                    continue;
                }
                else if (girl_love_fir[g][i] < girl_love_fir[g][girl[g]]) {
    
                    boy[girl[g]] = 0;
                    girl[g] = i;
                    boy[i] = g;
                }
                flag = true;
            }
        }
        if (no) break;
        if (!flag) break;
    }
    if (no) puts("Impossible");
    else for (int i = 1; i <= n; i++) cout << str[girl[i]] << " " << str[i + n] << endl;
}
int main() {
    
    while (~scanf("%d", &n)) {
    
        map<string, int> m, m2;
        int id = 0;
        string s;
        for (int i = 1; i <= n; i++) {
    
            cin >> s;
            m[s] = i;
            str[i] = s;
            for (int j = 1; j <= n; j++) {
    
                cin >> s;
                if (!m2[s]) {
    
                    m2[s] = ++id;
                    str[id + n] = s;
                }
                boy_love_who[i][j] = m2[s];
            }
        }
        for (int i = 1; i <= n; i++) {
    
            cin >> s;
            int x = m2[s];
            for (int j = 1; j <= n; j++) {
    
                cin >> s;
                girl_love_fir[x][m[s]] = j;
            }
        }
        G_S();
    }
    return 0;
}