Submission #7904581

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Source Code Expand

import sys
sys.setrecursionlimit(10**9)
input = sys.stdin.readline

N,M = map(int,input().split())
L = []
for i in range(N):
  tmp = list(map(int,input().split()))
  L.append(tmp[1:])

dicL = {}
for i in range(N):
  for l in L[i]:
    if l not in dicL:
      dicL[l] = [i]
    else:
      dicL[l].append(i)
#print(dicL)
E = [[] for _ in range(N)]
for k,v in dicL.items():
  if len(v) > 1:
    for i in range(len(v)-1):
      for j in range(i+1,len(v)):
        E[v[i]].append(v[j])
        E[v[j]].append(v[i])
for i in range(N):
  E[i] = set(E[i])
#print(E)
Visited = [0 for _ in range(N)]
def dfs(v):
  Visited[v] = 1
  for u in E[v]:
    if Visited[u] == 0:
      dfs(u)
dfs(0)
print('YES' if sum(Visited) == N else 'NO')

Submission Info

Judge Result