Submission #992220

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Source Code Expand

// tsukasa_diary's programing contest code template
#include <bits/stdc++.h>
using namespace std;
#define TSUKASA_DIARY_S_TEMPLATE
// define
#define for_(i,a,b) for(int i=(a);i<(b);++i)
#define for_rev(i,a,b) for(int i=(a);i>=(b);--i)
#define allof(a) (a).begin(),(a).end()
#define minit(a,b) memset(a,b,sizeof(a))
#define size_of(a) int((a).size())
#define cauto const auto
// typedef
typedef long long lint;
typedef double Double;
typedef pair< int, int > pii;
template< typename T > using Vec = vector< T >;
template< typename T > using Matrix = Vec< Vec< T > >;
template< typename T > using USet = unordered_set< T >;
template< typename T, class C > using MyUSet = unordered_set< T, C >;
template< typename T, typename F > using UMap = unordered_map< T, F >;
template< typename T, typename F, class C > using MyUMap = unordered_map< T, F, C >;
// hash
class PiiHash { public: size_t operator () (const pii& p) const { return (p.first << 16) | p.second; } };
// popcount
inline int POPCNT(int x) { return __builtin_popcount(x); }
inline int POPCNT(lint x) { return __builtin_popcount(x); }
// inf
const int iINF = 1L << 30;
const lint lINF = 1LL << 60;
// eps
const Double EPS = 1e-9;
const Double PI = acos(-1);
// inrange
template< typename T >
inline bool in_range(T v, T mi, T mx) { return mi <= v && v < mx; }
template< typename T >
inline bool in_range(T x, T y, T W, T H) { return in_range(x,0,W) && in_range(y,0,H); }
// neighbor clockwise
const int DX[4] = {0,1,0,-1}, DY[4] = {-1,0,1,0};
const int DX_[8] = {0,1,1,1,0,-1,-1,-1}, DY_[8] = {-1,-1,0,1,1,1,0,-1};
// variable update
template< typename T > inline void modAdd(T& a, T b, T mod) { a = (a + b) % mod; }
template< typename T > inline void modMul(T& a, T b, T mod) { a = (a * b) % mod; }
template< typename T > inline void minUpdate(T& a, T b) { a = min(a, b); }
template< typename T > inline void maxUpdate(T& a, T b) { a = max(a, b); }
// converter
template< typename F, typename T >
inline void convert(F& from, T& to) {
	stringstream ss;
	ss << from; ss >> to;
}

class UnionFind {
private:
	Vec< int > data;
	int num_of_g;
	
public:
	UnionFind(int n) : data(n, -1), num_of_g(n) {}
	
	bool unionSet(int x, int y) {
		x = root(x); y = root(y);
		
		if (x == y) return 0;
		
		if (data[y] < data[x]) swap(x, y);
		data[x] += data[y]; data[y] = x;
		--num_of_g;
		
		return 1;
	}
	
	bool sameSet(int x, int y) { return root(x) == root(y); }
	int root(int x) { return data[x] < 0 ? x : data[x] = root(data[x]); }
	int size(int x) { return -data[root(x)]; }
	int getNumOfG() { return num_of_g; }
};

int N, M;

int main() {
	cin >> N >> M;
	
	UnionFind uf(M);
	set< int > all_L;
	
	for_(i,0,N) {
		int K; cin >> K;
		int prev; cin >> prev; --prev;
		all_L.insert(prev);
		
		--K;
		for_(j,0,K) {
			int L; cin >> L; --L;
			all_L.insert(L);
			uf.unionSet(prev, L);
			prev = L;
		}
	}
	
	set< int > roots;
	for (int x : all_L) roots.insert(uf.root(x));
	cout << (roots.size() == 1 ? "YES": "NO") << endl;
}

Submission Info

Judge Result