// compile: g++ -o data data.cpp -O3 -std=gnu++20 -Wall -Wextra -Wshadow -D_GLIBCXX_ASSERTIONS -ggdb3 -fmax-errors=2 -DLOCAL // run: ./data < data.in #include <bits/stdc++.h> using namespace std; #pragma GCC optimize("O3,unroll-loops") #pragma GCC target("avx2,bmi,bmi2,lzcnt,popcnt") #ifdef LOCAL #include <debug/codeforces.h> #define debug(x...) {_variables(#x);_print(x);} #else #define debug(x...) #endif template<typename...Args> void print_(Args...args){((cout<<args<<" "),...)<<endl;} #define rep(i,a,b) for(int i=(a);i<(int)(b);++i) #define sz(v) ((int)(v).size()) #define print(...) print_(__VA_ARGS__); #define INTINF (int)(9223372036854775807) #define int long long #define MAXN 110 bool vis[MAXN][MAXN]; int32_t main() { ios::sync_with_stdio(false); cin.tie(nullptr); cout.tie(nullptr); int n, m; cin >> n >> m; rep(i, 0, m) { int k; cin >> k; vector<int> a(k); rep(j, 0, k) cin >> a[j], --a[j]; rep(x, 0, k) rep(y, 0, k) vis[a[x]][a[y]] = 1; } rep(i, 0, n) rep(j, 0, n) if (i!=j && !vis[i][j]) { cout << "No" << endl; return 0; } cout << "Yes" << endl; return 0; }
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