[백준] 효율적인 해킹.py

import sys
from collections import deque

def bfs(start, connected):
    queue = deque()
    queue.append(start)
    visited = [0 for _ in range(N+1)]
    count = 1
    while queue:
        current = queue.popleft()
        visited[current] = 1
        if connected[current]:
            for _next in connected[current]:
                if not visited[_next]:
                    count += 1
                    visited[_next] = 1
                    queue.append(_next)
    return count

N, M = map(int, sys.stdin.readline().split())
connected = [[] for _ in range(N+1)]
for _ in range(M):
    A, B = map(int, sys.stdin.readline().split())
    connected[B].append(A)
    
table = dict()

for i in range(1, N+1):
    if connected[i]:
        table[i] = bfs(i, connected)
max_value = max(table.values())
print(*sorted([i for (i,j) in table.items() if j == max_value]))