原文链接：
https://blog.csdn.net/Encore47/article/details/115127800

大佬的AC代码(供自己学习一下码风)

#include<stdio.h>
#include<iostream>
#include<vector>
#include<cstring>
#include<cstdio>
#include<climits>
#include<cmath>
#include<algorithm>
#include<queue>
#include<deque>
#include<map>
#include<unordered_map>
#include<set>
#include<unordered_set>
#include<stack>
#define VI vector<int>
#define eps 1e-6
#define io ios::sync_with_stdio(false); cin.tie(0); cout.tie(0)
using namespace std;
typedef long long LL;
typedef double db;
const int inf = 0x3f3f3f3f;
const LL INF = 1e18;
const int N = 1e5 + 10;
#define ls rt << 1
#define rs rt << 1 | 1
#define lson l, mid, rt << 1
#define rson mid + 1, r, rt << 1 | 1
inline int readint() {int x; scanf("%d", &x); return x;}

int cnt[N], res[N];
set<int> day[N];
int n, m;
void init() {
    for(int i = 1; i <= m; ++i) {
        day[i].clear();
    }
    memset(cnt, 0, sizeof(cnt));
    memset(res, 0, sizeof(res));
}

int main() {
#ifdef LOCAL
    freopen("input.txt", "r", stdin);
//   freopen("output.txt", "w", stdout);
#endif
    int t = readint();
    while (t--) {
        init();
        n = readint(), m = readint();
        for(int i = 1; i <= m; ++i) {
            int k = readint();
            while (k--) {
                int p = readint();
                day[i].insert(p);
                cnt[p]++;
            }
        }
        int ma = 0, lim = (m + 1) / 2;
        for(int i = 1; i <= n; ++i) {
            if (cnt[i] > lim) {
                ma = i; break;
            }
        }
        if (ma == 0) {
            printf("YES\n");
            for(int i = 1; i <= m; ++i) {
                auto it = day[i].begin();
                printf("%d%s", *it, i == m ? "\n" : " ");
            }
            continue;
        }
        int num = 0;

        for(int i = 1; i <= m; ++i) {
            if (res[i]) continue;
            if (day[i].size() == 1 && day[i].find(ma) != day[i].end()) {
                res[i] = ma;
                num++;
            }
        }
        if (num > lim) {
            printf("NO\n"); continue;
        }
        for(int i = 1; i <= m; ++i) {
            if (res[i]) continue;
            if (day[i].find(ma) != day[i].end() && num < lim) {
                res[i] = ma;
                num++;
                continue;
            }

            for(auto it = day[i].begin(); it != day[i].end(); ++it) {
                int now = *it;
                if (now != ma) {
                    res[i] = now;
                    break;
                }
            }
        }
        printf("YES\n");
        for(int i = 1; i <= m; ++i) {
            printf("%d%s", res[i], i == m ? "\n" : " ");
        }
    }
    return 0;
}

我的代码

#include <bits/stdc++.h>
using namespace std;
#define IO std::ios::sync_with_stdio(false); cin.tie(0)
#define ll long long
#define ull unsigned long long
#define SZ(x) ((int)(x).size())
#define all(x) (x).begin(), (x).end()
#define rep(i, l, r) for (int i = l; i <= r; ++i)
#define per(i, l, r) for (int i = l; i >= r; --i)
#define mset(s, _) memset(s, _, sizeof(s))
#define mcpy(s, _) memcpy(s, _, sizeof(s))
#define pb push_back
#define pii pair <int, int>
#define vi vector<int>
#define vpii vector<pii> 
#define mp(a, b) make_pair(a, b)
#define debug system("pause")
#define pll pair <ll, ll>
#define fir first
#define sec second
#define inf 0x3f3f3f3f
#define pline cout << endl << endl 
inline int lowbit(int x) {return x & -x;} 
template< typename T > inline void get_min(T &x, T y) {if(y < x) x = y;}
template< typename T > inline void get_max(T &x, T y) {if(x < y) x = y;}
inline int read() {
  int x = 0, f = 0; char ch = getchar();
  while (!isdigit(ch)) f |= ch == '-', ch = getchar();
  while (isdigit(ch)) x = 10 * x + ch - '0', ch = getchar();
  return f ? -x : x;
}
template<typename T> inline void print(T x) {
  if (x < 0) putchar('-'), x = -x;
  if (x >= 10) print(x / 10);
  putchar(x % 10 + '0');
}
template<typename T> inline void print(T x, char let) {
  print(x), putchar(let);
}

const int N = 2e5 + 10, mod = 100019;
int t, n, m; 
int cnt[N], st[N], ans[N];
set<int> day[N];

void init() {
    rep(i, 0, m) day[i].clear();
    mset(cnt, 0); mset(st, 0); mset(ans, 0);
}

int main() {
    cin >> t;
    while(t -- ) {
        init();
        cin >> n >> m;
        rep(d, 1, m) {
            int num; cin >> num;
            int p;
            rep(j, 1, num) {
                cin >> p; day[d].insert(p); cnt[p] ++ ;
            } 
        }
        int rnd = (m + 1) >> 1, mk = 0;
        rep(i, 1, n) {
            if(cnt[i] > rnd) {
                mk = i; break;
            }
        }

        if(!mk) {
            puts("YES");
            rep(i, 1, m) {
                auto it = day[i].begin(); cout << *it << ' ';
            }
            cout << endl;
            continue;
        } 

        int num = 0;
        rep(i, 1, m) {
            if(day[i].size() == 1 && day[i].find(mk) != day[i].end()) {
                st[i] = 1; num ++ ; ans[i] = mk;
            }
        }
        if(num > rnd) {
            puts("NO"); continue;
        }

        rep(i, 1, m) {
            if(!st[i] && day[i].find(mk) != day[i].end() && num < rnd) {
                st[i] = 1; ans[i] = mk; num ++ ;
                continue;
            }

            if(!st[i]) {
                for(auto j : day[i]) {
                    if(j != mk) {
                        ans[i] = j; break;
                    }
                }
            }
        }

        puts("YES");
        rep(i, 1, m) cout << ans[i] << ' ';
        cout << endl;
    }

    return 0; 
}