Submission #991858

---

Source Code Expand

#include <bits/stdc++.h>

using namespace std;

typedef long long ll;
typedef unsigned long long ull;
typedef long double ld;
typedef pair<ll, ll> P;

#define EACH(i,a) for (auto& i : a)
#define FOR(i,a,b) for (ll i=(a);i<(b);i++)
#define RFOR(i,a,b) for (ll i=(b)-1;i>=(a);i--)
#define REP(i,n) for (ll i=0;i<(n);i++)
#define RREP(i,n) for (ll i=(n)-1;i>=0;i--)
#define debug(x) cout<<#x<<": "<<x<<endl
#define pb push_back
#define ALL(a) (a).begin(),(a).end()

const ll linf = 1e18;
const int inf = 1e9;
const double eps = 1e-12;
const double pi = acos(-1);

template<typename T>
istream& operator>>(istream& is, vector<T>& vec) {
    EACH(x,vec) is >> x;
    return is;
}
template<typename T>
ostream& operator<<(ostream& os, vector<T>& vec) {
    REP(i,vec.size()) {
        if (i) os << " ";
        os << vec[i];
    }
    return os;
}
template<typename T>
ostream& operator<<(ostream& os, vector< vector<T> >& vec) {
    REP(i,vec.size()) {
        if (i) os << endl;
        os << vec[i];
    }
    return os;
}

class UnionFind {
    vector<int> par, h;
public:
    UnionFind(int size) {
        par.assign(size, 0);
        h.assign(size, 0);
        REP(i, size) par[i] = i;
    }
    void unite(int u, int v) {
        u = root(u), v = root(v);
        if (u == v) return;
        if (h[u] > h[v]) {
            par[v] = u;
        }
        else if (h[u] < h[v]) {
            par[u] = v;
        }
        else {
            ++h[u];
            par[v] = u;
        }
    }
    bool isUnited(int u, int v) {
        return root(u) == root(v);
    }
    int root(int v) {
        if (par[v] == v) return v;
        return par[v] = root(par[v]);
    }
};

int main() {
    std::ios::sync_with_stdio(false);
    std::cin.tie(0);
    int n, m; cin >> n >> m;
    vector< vector<int> > L(m);
    REP(i, n) {
        int K; cin >> K;
        REP(j, K) {
            int l; cin >> l; --l;
            L[l].pb(i);
        }
    }
    UnionFind uf(n);
    REP(i, m) {
        FOR(j, 1, L[i].size()) {
            uf.unite(L[i][j-1], L[i][j]);
        }
    }
    set<int> s;
    REP(i, n) s.insert( uf.root(i) );
    if (s.size() == 1) {
        cout << "YES" << endl;
    }
    else {
        cout << "NO" << endl;
    }
}

Submission Info

Judge Result