Problem p03855 (python)

Fixed submission:
from collections import defaultdict
class UnionFind(object):
  def __init__(self,n=1):
    self.par = [i for i in range(n)]
    self.rank = [0 for _ in range(n)]
    self.size = [1 for _ in range(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 union(self,x,y):
    x = self.find(x)
    y = self.find(y)
    if x != y :
      if self.rank[x] <self.rank[y]:
        x,y = y,x
      if self.rank[x] == self.rank[y]:
        self.rank[x] += 1
      self.par[y] = x
      self.size[x] +=self.size[y]

  def is_same(self,x,y):
    return self.find(x)==self.find(y)
  
  def get_size(self,x):
    x = self.find(x)
    return self.size[x]

N, K, L = map(int, input().split())

# 道路のUnionFind
uf1 = UnionFind(N)
for i in range(K):
    p, q = map(int, input().split())
    uf1.union(p - 1, q - 1)
 
# 鉄道のUnionFind
uf2 = UnionFind(N)
for i in range(L):
    r, s = map(int, input().split())
    uf2.union(r - 1, s - 1)
 
# 道路と鉄道の連結の組み合わせ（根のペアのカウント）
c = defaultdict(int)
for i in range(N):
    c[(uf1.find(i), uf2.find(i))] += 1
ans = ""

# 回答を出力
for i in range(N):
    ans += str(c[(uf1.find(i), uf2.find(i))]) + " "
print(ans)

Buggy submission (verdict: Runtime Error):
from collections import defaultdict
class UnionFind(object):
  def __init__(self,n=1):
    self.par = [i for i in range(n)]
    self.rank = [0 for _ in range(n)]
    self.size = [1 for _ in range(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 union(self,x,y):
    x = self.find(x)
    y = self.find(y)
    if x != y :
      if self.rank[x] <self.rank[y]:
        x,y = y,x
      if self.rank[x] == self.rank[y]:
        self.rank[x] += 1
      self.par[y] = x
      self.size[x] +=self.size[y]

  def is_same(self,x,y):
    return self.find(x)==self.find(y)
  
  def get_size(self,x):
    x = self.find(x)
    return self.size[x]

N, K, L = map(int, input().split())

# 道路のUnionFind
uf1 = UnionFind(N)
for i in range(K):
    p, q = map(int, input().split())
    uf1.union(p - 1, q - 1)
 
# 鉄道のUnionFind
uf2 = UnionFind(N)
for i in range(L):
    r, s = map(int, input().split())
    uf2.union(r - 1, s - 1)
 
# 道路と鉄道の連結の組み合わせ（根のペアのカウント）
c = defaultdict(int)
for i in range(N):
    c[(uf1.find(i), uf2.find(i))] += 1
ans = ""

# 回答を出力
for i in range(N):
    ans += str(c[(uf1.find(i), uf2.find(i))]) + " "
print(ans)

Buggy submission (verdict: Runtime Error):
from collections import defaultdict
class UnionFind(object):
  def __init__(self,n=1):
    self.par = [i for i in range(n)]
    self.rank = [0 for _ in range(n)]
    self.size = [1 for _ in range(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 union(self,x,y):
    x = self.find(x)
    y = self.find(y)
    if x != y :
      if self.rank[x] <self.rank[y]:
        x,y = y,x
      if self.rank[x] == self.rank[y]:
        self.rank[x] += 1
      self.par[y] = x
      self.size[x] +=self.size[y]

  def is_same(self,x,y):
    return self.find(x)==self.find(y)
  
  def get_size(self,x):
    x = self.find(x)
    return self.size[x]

N, K, L = map(int, input().split())

# 道路のUnionFind
uf1 = UnionFind(N)
for i in range(K):
    p, q = map(int, input().split())
    uf1.union(p - 1, q - 1)
 
# 鉄道のUnionFind
uf2 = UnionFind(N)
for i in range(L):
    r, s = map(int, input().split())
    uf2.union(r - 1, s - 1)
 
# 道路と鉄道の連結の組み合わせ（根のペアのカウント）
c = defaultdict(int)
for i in range(N):
    c[(uf1.find(i), uf2.find(i))] += 1
ans = ""
# 回答を出力
for i in range(N):
    ans += str(c[(uf1.find(i), uf2.find(i))]) + " "
print(ans)