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


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

    def _root(self, x):
        stack = []
        tbl = self.table
        while tbl[x] >= 0:
            stack.append(x)
            x = tbl[x]
        for y in stack:
            tbl[y] = x
        return x

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

    def union(self, x, y):
        r1 = self._root(x)
        r2 = self._root(y)
        if r1 == r2:
            return
        d1 = self.table[r1]
        d2 = self.table[r2]
        if d1 <= d2:
            self.table[r2] = r1
            self.table[r1] += d2
        else:
            self.table[r1] = r2
            self.table[r2] += d1


def main():
    n, m, k = map(int, sys.stdin.buffer.readline().split())
    uf = UnionFind(n)
    fb = [0]*n
    i = 0
    for x in sys.stdin.buffer.readlines():
        print(uf.table)
        if i < m:
            a, b = map(int, x.split())
            fb[a-1] += 1
            fb[b-1] += 1
            uf.union(a-1, b-1)
        else:
            c, d = map(int, x.split())
            if uf._root(c-1) == uf._root(d-1):
                fb[c-1] += 1
                fb[d-1] += 1
        i += 1

    ans = [-uf.table[uf._root(i)]-1-fb[i] for i in range(n)]
    print(*ans)


if __name__ == "__main__":
    main()


n, m, k = map(int, input().split())
table = [[0 for i in range(n+1)] for j in range(n+1)]
for i in range(m):
    a, b = map(int, input().split())
    table[min(a,b)][max(a,b)] = 1
for i in range(k):
    c, d = map(int, input().split())
    table[max(c,d)][min(c,d)] = -1

ans = [0 for i in range(n)]

for i in range(1, n+1):
    for j in range(i+1, n+1):
        check = 0
        if table[i][j] == 0 and table[j][i] != -1:
            for k in range(i, j-1):
                if table[k][k+1] != 1 or table[k+1][k] == -1:
                    check = 1
            if check == 0:
                ans[i-1] += 1
                ans[j-1] += 1
for i in ans:
    print(i, end = " ")

import sys


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

    def _root(self, x):
        stack = []
        tbl = self.table
        while tbl[x] >= 0:
            stack.append(x)
            x = tbl[x]
        for y in stack:
            tbl[y] = x
        return x

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

    def union(self, x, y):
        r1 = self._root(x)
        r2 = self._root(y)
        if r1 == r2:
            return
        d1 = self.table[r1]
        d2 = self.table[r2]
        if d1 <= d2:
            self.table[r2] = r1
            self.table[r1] += d2
        else:
            self.table[r1] = r2
            self.table[r2] += d1


def main():
    n, m, k = map(int, sys.stdin.buffer.readline().split())
    uf = UnionFind(n)
    fb = [0]*n
    i = 0
    for x in sys.stdin.buffer.readlines():
        if i < m:
            a, b = map(int, x.split())
            fb[a-1] += 1
            fb[b-1] += 1
            uf.union(a-1, b-1)
        else:
            c, d = map(int, x.split())
            if uf._root(c-1) == uf._root(d-1):
                fb[c-1] += 1
                fb[d-1] += 1
        i += 1

    ans = [-uf.table[uf._root(i)]-1-fb[i] for i in range(n)]
    print(*ans)


if __name__ == "__main__":
    main()


Verdicts: Runtime Error

Wrong Answer

Accepted