Submission #992297

---

Source Code Expand

#include <vector>
#include <list>
#include <map>
#include <set>
#include <queue>
#include <deque>
#include <stack>
#include <bitset>
#include <algorithm>
#include <functional>
#include <numeric>
#include <utility>
#include <sstream>
#include <iostream>
#include <iomanip>
#include <cstdio>
#include <cmath>
#include <cstdlib>
#include <cctype>
#include <string>
#include <cstring>
#include <ctime>
#include <climits>

#define int long long
#define FOR(i, a, b) for (int i = (a); i < (b); ++i)
#define REP(i, n) FOR(i, 0, n)
#define ALL(a) (a).begin(), (a).end()
#define PB push_back
#define MP make_pair
#define FST first
#define SND second
#define SZ(a) (signed)((a).size())
#define EACH(i, c) for (typeof((c).begin()) i = (c).begin(); i != (c).end(); ++i)
#define EXIST(s, e) ((s).find(e) != (s).end())
#define SORT(c) sort((c).begin(), (c).end())

using namespace std;

typedef vector<int> VI;
typedef vector<VI> VVI;
typedef vector<string> VS;
typedef pair<int, int> PII;

const int MOD = 1000000007;

#define dump(x) cerr << #x << " = " << (x) << endl;
#define debug(x) cerr << #x << " = " << (x) << " (L" << __LINE__ << ")"  << " " << __FILE__ << endl;

class UnionFind {
    vector<int> pir;

public:
    UnionFind(int size) : pir(size, -1) { }

    bool unite(int x, int y) {
        x = root(x);
        y = root(y);
        if (x != y) {
            if (pir[y] < pir[x]) swap(x, y);
            pir[x] += pir[y];
            pir[y] = x;
        }
        return x != y;
    }

    bool same(int x, int y) {
        return root(x) == root(y);
    }

    int root(int x) {
        if (pir[x] < 0) {
            return x;
        } else {
            return pir[x] = root(pir[x]);
        }
    }

    int size(int x) {
        return -pir[root(x)];
    }
};

signed main(void) {
    ios::sync_with_stdio(false);
    cout.setf(ios::fixed, ios::floatfield);
    cout.precision(10);
    cin.tie(0);

    int n,m;
    cin >> n >> m;

    VI k(n);
    VVI l(n,VI());
    REP(i,n){
        cin >> k[i];
        REP(j,k[i]){
            int t;
            cin >> t;
            l[i].push_back(t);
        }
    }

    UnionFind uf(m);
    REP(i,n){
        FOR(j,1,k[i]){
            uf.unite(l[i][0],l[i][j]);
        }
    }

    FOR(i,1,n){
        if(!uf.same(l[0][0],l[i][0])){
            cout << "NO" << endl;
            return 0;
        }
    }
    cout << "YES" << endl;
    return 0;
}

Submission Info

Judge Result