[Python] 백준 2606 바이러스

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

풀이

#DFS
from collections import deque

def virus(graph, start, visited):
    queue = deque([start])
    
    visited[start] = True
    
    count = 0
        
    while queue:
        V = queue.popleft()
        
        count += 1    
            
        for i in graph[V]:
            if not visited[i]:
                queue.append(i)
                visited[i] = True
    print(count - 1)
                

N = int(input())
M = int(input())

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

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

visited = [False] * (N + 1)
virus(graph, 1, visited)