Problem p02762 (python)

Fixed submission:
class UnionFind():
    def __init__(self, n):
        self.n = n
        self.parents = [-1] * n

    def find(self, x):
        if self.parents[x] < 0:
            return x
        else:
            self.parents[x] = self.find(self.parents[x])
            return self.parents[x]

    def union(self, x, y):
        x = self.find(x)
        y = self.find(y)

        if x == y:
            return

        if self.parents[x] > self.parents[y]:
            x, y = y, x

        self.parents[x] += self.parents[y]
        self.parents[y] = x

    def size(self, x):
        return -self.parents[self.find(x)]

    def same(self, x, y):
        return self.find(x) == self.find(y)

    def members(self, x):
        root = self.find(x)
        return [i for i in range(self.n) if self.find(i) == root]

    def roots(self):
        return [i for i, x in enumerate(self.parents) if x < 0]

    def group_count(self):
        return len(self.roots())

    def all_group_members(self):
        return {r: self.members(r) for r in self.roots()}

    def __str__(self):
        return '\n'.join('{}: {}'.format(r, self.members(r)) for r in self.roots())
      
n, m, k = map(int, input().split())
uf = UnionFind(n)
E = [[] for i in range(n)]
num_E = [0]*n
E_d = [[] for i in range(n)]

import sys
input = sys.stdin.readline

for i in range(m):
  a, b = map(int, input().split())
  a -= 1
  b -= 1
  uf.union(a, b)
  num_E[a] += 1
  num_E[b] += 1

for i in range(k):
  a, b = map(int, input().split())
  a -= 1
  b -= 1
  E_d[a] = E_d[a] + [b]
  E_d[b] = E_d[b] + [a]

num_men = [0]*n
for i in range(n):
  num_men[i] = uf.size(i) - 1
  for dn in E_d[i]:
    if uf.same(i, dn):
      num_men[i] -= 1
  num_men[i] -= num_E[i]
      
print(*num_men)

Buggy submission (verdict: Runtime Error):
class UnionFind():
    def __init__(self, n):
        self.n = n
        self.parents = [-1] * n

    def find(self, x):
        if self.parents[x] < 0:
            return x
        else:
            self.parents[x] = self.find(self.parents[x])
            return self.parents[x]

    def union(self, x, y):
        x = self.find(x)
        y = self.find(y)

        if x == y:
            return

        if self.parents[x] > self.parents[y]:
            x, y = y, x

        self.parents[x] += self.parents[y]
        self.parents[y] = x

    def size(self, x):
        return -self.parents[self.find(x)]

    def same(self, x, y):
        return self.find(x) == self.find(y)

    def members(self, x):
        root = self.find(x)
        return [i for i in range(self.n) if self.find(i) == root]

    def roots(self):
        return [i for i, x in enumerate(self.parents) if x < 0]

    def group_count(self):
        return len(self.roots())

    def all_group_members(self):
        return {r: self.members(r) for r in self.roots()}

    def __str__(self):
        return '\n'.join('{}: {}'.format(r, self.members(r)) for r in self.roots())
      
n, m, k = map(int, input().split())
uf = UnionFind(n)
E = [[] for i in range(n)]
num_E = [0]*n
E_d = [[] for i in range(n)]

import sys
input = sys.stdin.readline

for i in range(m):
  a, b = map(int, input().split())
  a -= 1
  b -= 1
  uf.union(a, b)
  E[a] += 1
  E[b] += 1

for i in range(k):
  a, b = map(int, input().split())
  a -= 1
  b -= 1
  E_d[a] = E_d[a] + [b]
  E_d[b] = E_d[b] + [a]

num_men = [0]*n
for i in range(n):
  num_men[i] = uf.size(i) - 1
  for dn in E_d[i]:
    if uf.same(i, dn):
      num_men[i] -= 1
  num_men[i] -= E[i]
      
print(*num_men)