Problem p02762 (python)

Fixed submission:
class UnionFind():
    def __init__(self, n):
        self.n = n
        self.parents = [-1] * n
    
    def root(self, x):
        if self.parents[x] < 0:
            return x
        else:
            self.parents[x] = self.root(self.parents[x])
            return self.parents[x]
    
    def unite(self, x, y):
        x = self.root(x)
        y = self.root(y)

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

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

    def size(self, x):
        return -self.parents[self.root(x)]
    
    def members(self, x):
        x_root = self.root(x)
        return [i for i in range(self.n) if self.root(i) == x_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)

friend = [0] * N
block = [[]*N for i in range(N)]

for _ in range(M):
    a, b = map(int, input().split())
    a -= 1
    b -= 1
    friend[a] += 1
    friend[b] += 1
    uf.unite(a, b)

for _ in range(K):
    a, b = map(int, input().split())
    a -= 1
    b -= 1
    block[a].append(b)
    block[b].append(a)

for i in range(N):
    ans = uf.size(i) - 1
    ans -= friend[i]
    for br in block[i]:
        if uf.same(i, br):
            ans -= 1
    print(ans)

Buggy submission (verdict: Runtime Error):
class UnionFind():
    def __init__(self, n):
        self.n = n
        self.parents = [-1] * n
    
    def root(self, x):
        if self.parents[x] < 0:
            return x
        else:
            self.parents[x] = self.root(self.parents[x])
            return self.parents[x]
    
    def unite(self, x, y):
        x = self.root(x)
        y = self.root(y)

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

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

    def size(self, x):
        return -self.parents[self.root(x)]
    
    def members(self, x):
        x_root = self.root(x)
        return [i for i in range(self.n) if self.root(i) == x_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)

friend = [] * N
block = [[]*N for i in range(N)]

for _ in range(M):
    a, b = map(int, input().split())
    a -= 1
    b -= 1
    friend[a] += 1
    friend[b] += 1
    uf.unite(a, b)

for _ in range(K):
    a, b = map(int, input().split())
    a -= 1
    b -= 1
    block[a].append(b)
    block[b].append(a)

for i in range(N):
    ans = uf.size(i)
    ans -= friend[i]
    for br in block[i]:
        if uf.same(i, br):
            ans -= 1
    print(ans)