Submission #3141639

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Source Code Expand

import sys
sys.setrecursionlimit(100000)

n,m=map(int,input().split())
f=lambda x:int(x)-1

langs=[[] for _ in range(m)]
speakers=[[] for _ in range(n)]
used_langs=[False]*m
used_speakers=[False]*n

for i in range(n):
  *l,=map(f,input().split()[1:])
  speakers[i].extend(l)
  for j in l:
    langs[j].append(i)

def dfs(n):
  if used_speakers[n]:
    return
  used_speakers[n]=True
  for i in speakers[n]:
    if used_langs[i]:continue
    used_langs[i]=True
    for j in langs[i]:
      dfs(j)

dfs(0)
if not False in used_speakers:
  print("YES")
else:
  print("NO")

Submission Info

Judge Result