Submission #993347

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Source Code Expand

#include <iostream>
#include <sstream>
#include <algorithm>
#include <string>
#include <vector>
#include <map>
#include <set>
#include <queue>
#include <deque>
#include <stack>
#include <memory>
#include <complex>
#include <numeric>
#include <cstdio>
#include <iomanip>

#define REP(i,m,n) for(int i=int(m);i<int(n);i++)
#define EACH(i,c) for (auto &(i): c)
#define all(c) begin(c),end(c)
#define EXIST(s,e) ((s).find(e)!=(s).end())
#define SORT(c) sort(begin(c),end(c))
#define pb emplace_back
#define MP make_pair
#define SZ(a) int((a).size())

#ifdef LOCAL
#define DEBUG(s) cout << (s) << endl
#define dump(x)  cerr << #x << " = " << (x) << endl
#define BR cout << endl;
#else
#define DEBUG(s) do{}while(0)
#define dump(x) do{}while(0)
#define BR 
#endif
using namespace std;

using UI = unsigned int;
using UL = unsigned long;
using LL = long long int;
using ULL = unsigned long long;
using VI = vector<int>;
using VVI = vector<VI>;
using VLL = vector<LL>;
using VS = vector<string>;
using PII = pair<int,int>;
using VP = vector<PII>;

constexpr double EPS = 1e-10;
constexpr double PI  = acos(-1.0);

template<class T> inline T sqr(T x) {return x*x;}

class UnionFind {
    struct UFNode {
        int par;
        int rank;
    };
    vector<UFNode> nodes;
public:
    UnionFind(int n): nodes(n) {
        for (int i = 0; i < n; i++) {
            nodes[i].par = i;
            nodes[i].rank = 0;
        }
    };
    int root(int x) {
        return nodes[x].par == x ? x : nodes[x].par = root(nodes[x].par);
    }
    bool same(int x, int y) {
        return root(x) == root(y);
    }
    void unite(int x, int y) {
        x = root(x);
        y = root(y);
        if (x == y) return;
        if (nodes[x].rank < nodes[y].rank) {
            nodes[x].par = y;
        } else {
            nodes[y].par = x;
            if (nodes[x].rank == nodes[y].rank) nodes[x].rank++;
        }
    }
    //~UnionFind() {cout << nodes.size() << endl;}
};

int ary[100001];

int r[100001];

int main() {
	int n, m;
	cin >> n >> m;
	UnionFind u(m+1);
	int k, in;
	REP(i,0,n) {
		cin >> k;
        REP(j,0,k) {
            cin >> ary[j];
            //if (j > 0) u.unite(ary[j], ary[j-1]);
        }
        REP(j,1,k) u.unite(ary[j], ary[j-1]);
    }
    //return 0;
	REP(i,0,m+1) {
		r[u.root(i)]++;
        //cout << u.root(i) << endl;
	}
	bool b = false;
	REP(i,0,m+1) {
		if (r[i] > 1) {
			if (b) {
				cout << "NO" << endl;
				return 0;
			} else {
				b = true;
			}
		}
	}
	if (b) cout << "YES" << endl;
	else cout << "NO" << endl;

	return 0;
}

Submission Info

Judge Result