Submission #1481660

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Source Code Expand

#include <algorithm>
#include <cstdio>
#include <iostream>
#include <map>
#include <cmath>
#include <queue>
#include <set>
#include <sstream>
#include <stack>
#include <string>
#include <vector>
#include <stdlib.h>
#include <stdio.h>
#include <bitset>
using namespace std;
#define FOR(I,A,B) for(int I = (A); I < (B); ++I)
typedef long long ll;
// Union-Find
// ある人が喋れる言語は全て同じグループとする(翻訳したら同じになる)
// union - find tree !!!!!!!!!!!!!!!!!!!!!!!!!
vector<int> par; //oya
vector<int> rnk; //ki no hu ka sa
// n要素で初期化
void init(int n){
    par.resize(n);rnk.resize(n);
    FOR(i, 0, n){par[i] = i;rnk[i] = 0;}
}
//木の根を求める
int find(int x){
    if(par[x] == x) return x;
    else return par[x] = find(par[x]);
}
//xとyの属する集合を併合
void unite(int x, int y){
    x = find(x);y = find(y);
    if(x == y) return;
    if(rnk[x] < rnk[y])par[x] = y;
    else{par[y] = x;if(rnk[x] == rnk[y]) rnk[x]++;}
    return;
}
bool isSame(int x, int y){return find(x) == find(y);}
int main()
{
  int N, M;
  cin >> N >> M;
  init(100005);
  bool use[100005];
  FOR(i,0,100005) use[i] = false;
  FOR(i,0,N) {
    int K;
    cin >> K;
    int pre;
    cin >> pre;
    FOR(j, 0, K - 1) {
      int L;
      cin >> L;
      use[L] = true;
      unite(pre, L);
      pre = L;
    }
  }
  int x = 0;
  while(!use[x]) x++;
  int oya = find(x);
  FOR(i,0,100005) {
    if(use[i] && find(i) != oya) {
      puts("NO");
      return 0;
    }
  }
  puts("YES");
  return 0;
}

Submission Info

Judge Result