HDU 1914 the stable marriage problem

The question ： Stable marriage matching problem , Board question .

Answer key ： Stable marriage matching
Pay attention to output in dictionary order , And the output format , The last example does not output blank lines .

#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;
const int maxn = 33;
int t, n;

int boy_love_who[maxn][maxn], girl_love_fir[maxn][maxn];
int boy[maxn], girl[maxn], kth[maxn];
char str[maxn << 1];
struct node {
    
    int a, b;
    bool operator<(const node x)const {
    
        return a < x.a;
    }
}ans[maxn];
inline void G_S() {
    
    for (int i = 1; i <= n; i++) boy[i] = girl[i] = kth[i] = 0;
    bool flag, no = 0;
    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++) ans[i] = {
     str[girl[i]], str[i + n] };
        sort(ans + 1, ans + n + 1);
        for (int i = 1; i <= n; i++) printf("%c %c\n", ans[i].a, ans[i].b);
        puts("");
    }
}
char s[33];
int main() {
    
    scanf("%d", &t);
    while (t--) {
    
        scanf("%d", &n);
        map<char, int> m1, m2;
        for (int i = 1; i <= n; i++) {
    
            scanf("%s", s);
            m1[s[0]] = i;
            str[i] = s[0];
        }
        for (int i = 1; i <= n; i++) {
    
            scanf("%s", s);
            m2[s[0]] = i;
            str[i + n] = s[0];
        }
        for (int i = 1; i <= n; i++) {
    
            scanf("%s", s);
            int x = m1[s[0]];
            for (int j = 2; j <= n + 1; j++) {
    
                int y = m2[s[j]];
                boy_love_who[i][j - 1] = y;
            }
        }
        for (int i = 1; i <= n; i++) {
    
            scanf("%s", s);
            int x = m2[s[0]];
            for (int j = 2; j <= n + 1; j++) {
    
                int y = m1[s[j]];
                girl_love_fir[i][y] = j - 1;
            }
        }
        G_S();
    }
	return 0;
}