Problem: An SNS has N users - User 1, User 2, \cdots, User N.  Between these N users, there are some relationships - M _friendships_ and K _blockships_.  For each i = 1, 2, \cdots, M, there is a bidirectional friendship between User A_i and User B_i.  For each i = 1, 2, \cdots, K, there is a bidirectional blockship between User C_i and User D_i.  We define User a to be a _friend candidate_ for User b when all of the following four conditions are satisfied:    * a \neq b.   * There is not a friendship between User a and User b.   * There is not a blockship between User a and User b.   * There exists a sequence c_0, c_1, c_2, \cdots, c_L consisting of integers between 1 and N (inclusive) such that c_0 = a, c_L = b, and there is a friendship between User c_i and c_{i+1} for each i = 0, 1, \cdots, L - 1.  For each user i = 1, 2, ... N, how many friend candidates does it have?

Submission attempts (in order):
import sys
from collections import defaultdict, Counter


class UnionFind(object):
    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 main():
    n, m, k = list(map(int, sys.stdin.readline().strip().split()))

    friends = defaultdict(set)
    blocks = defaultdict(set)

    for i in range(m):
        a, b = list(map(int, sys.stdin.readline().strip().split()))
        a -= 1
        b -= 1
        friends[a].add(b)
        friends[b].add(a)

    for i in range(k):
        c, d = list(map(int, sys.stdin.readline().strip().split()))
        c -= 1
        d -= 1
        blocks[c].add(d)
        blocks[d].add(c)

    uf = UnionFind(n)

    for f_key in friends:
        for child in friends[f_key]:
            # child_cur_group = parents[child]
            uf.union(f_key, child)

    
    
    
    #     group_num_set[group].add(i)
    #
    # ans = [0] * n
    
    
    #     friend_cand = group_num_set[group]
    #     true_friend_cand = friend_cand.difference(blocks[i]).difference(friends[i])
    #     ans[i] = len(true_friend_cand) - 1
    #
    # return ans
    return [0]


result = main()
print(' '.join([str(num) for num in result]))


import sys
from collections import defaultdict, Counter


class UnionFind(object):
    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 main():
    n, m, k = list(map(int, sys.stdin.readline().strip().split()))

    friends = defaultdict(set)
    blocks = defaultdict(set)

    for i in range(m):
        a, b = list(map(int, sys.stdin.readline().strip().split()))
        a -= 1
        b -= 1
        friends[a].add(b)
        friends[b].add(a)

    for i in range(k):
        c, d = list(map(int, sys.stdin.readline().strip().split()))
        c -= 1
        d -= 1
        blocks[c].add(d)
        blocks[d].add(c)

    uf = UnionFind(n)

    for f_key in friends:
        for child in friends[f_key]:
            # child_cur_group = parents[child]
            uf.union(f_key, child)

    group_num_set = defaultdict(set)
    for i in range(n):
        group = uf.find(i)
        group_num_set[group].add(i)
    #
    # ans = [0] * n
    
    
    #     friend_cand = group_num_set[group]
    #     true_friend_cand = friend_cand.difference(blocks[i]).difference(friends[i])
    #     ans[i] = len(true_friend_cand) - 1
    #
    # return ans
    return [0]


result = main()
print(' '.join([str(num) for num in result]))


import sys
from collections import defaultdict, Counter


class UnionFind(object):
    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 main():
    n, m, k = list(map(int, sys.stdin.readline().strip().split()))

    friends = defaultdict(set)
    blocks = defaultdict(set)

    for i in range(m):
        a, b = list(map(int, sys.stdin.readline().strip().split()))
        a -= 1
        b -= 1
        friends[a].add(b)
        friends[b].add(a)

    for i in range(k):
        c, d = list(map(int, sys.stdin.readline().strip().split()))
        c -= 1
        d -= 1
        blocks[c].add(d)
        blocks[d].add(c)

    uf = UnionFind(n)

    for f_key in friends:
        for child in friends[f_key]:
            # child_cur_group = parents[child]
            uf.union(f_key, child)

    
    
    
    #     group_num_set[group].add(i)

    ans = [0] * n
    for i in range(n):
        group = uf.find(i)
        size = uf.size(i) - 1
        size -= len(friends[i])
        for block in blocks[i]:
            block_group = uf.find(block)
            if block_group == group:
                size -= 1
        ans[i] = size


        # friend_cand = group_num_set[group]

        # true_friend_cand = friend_cand.difference(blocks[i]).difference(friends[i])
        # ans[i] = len(true_friend_cand) - 1

    return ans


result = main()
print(' '.join([str(num) for num in result]))


Verdicts: Wrong Answer

Wrong Answer

Accepted