Submission #11232274

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Source Code Expand

class UnionFind:
  def __init__(self, n):
    self.par = [i for i in range(n)]
    self.rank = [0]*n
  def find(self, x):
    if self.par[x]==x:
      return x
    else:
      self.par[x] = self.find(self.par[x])
      return self.par[x]
  def unit(self, x, y):
    x = self.find(x)
    y = self.find(y)
    if x==y:
      return
    elif self.rank[x]<self.rank[y]:
      self.par[x] = y
      return
    elif self.rank[y]<self.rank[x]:
      self.par[y] = x
    else:
      self.par[y] = x
      self.rank[x] += 1
      
  def same(self, x, y):
    return self.find(x)==self.find(y)
  
N,M = map(int, input().split())
u = UnionFind(N+M)
for i in range(N):
  inf = list(map(int, input().split()))
  for l in inf[1:]:
    u.unit(i,N+l-1)

ans = all(u.same(i,i+1) for i in range(N-1))
if ans:
  print('Yes')
else:
  print('No')

Submission Info

Judge Result