[백준/2606] 바이러스

Baekjoon Online Judge - 2606

• 방문한 노드의 갯수를 새면 되는 문제

import collections

def bfs(start):
    queue = collections.deque()
    visited = [start]
    queue += graph[start]
    count = 0

    while queue:
        node = queue.popleft()
        if node not in visited:
            queue += graph[node]
            visited.append(node)
            # visited 리스트에 노드를 넣을 때마다 count 1씩 증가
            count += 1
    return count

V = int(input())
E = int(input())

graph = [[] for _ in range(V+1)]

for _ in range(E):
    a, b = map(int, input().split())
    graph[a].append(b)
    graph[b].append(a)

print(bfs(1))