[백준,PS,그래프탐색][PYTHON] #2606. 바이러스

https://www.acmicpc.net/problem/2606

from collections import deque

def bfs(x):
    global count
    
    visited[x] = 1
    q.append(x)
    
    while q:
        x = q.popleft()
        
        for i in range(len(a[x])):
            w = a[x][i]
            if (visited[w] != 1):
                visited[w] =1
                count +=1#인접한곳을 갈때마다 count를 1씩 증가시켜서 연결된것이 전부 몇개인지 확인해준다.
                q.append(w)
        
node = int(input())
edge = int(input())

a =[ [] for _ in range(node+1)]
visited =[ 0 for _ in range(node +1)]
count = 0
q = deque()

for i in range(edge):
    x,y = map(int, input().split())
    a[x].append(y)
    a[y].append(x)

bfs(1)#BFS 시작
print(count)