[백준 11724] 연결 요소의 개수 - Python

from collections import deque
import sys
sys.setrecursionlimit(10**6)
input = sys.stdin.readline
n , m = map(int,input().split())

graph= [[]*(n+1) for i in range(n+1)]
visited = [False] * (n+1)

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

def bfs(startNode):
    queue = deque([startNode])
    while(queue):
        startNode = queue.popleft()
        for i in graph[startNode]:
            if visited[i]==False:
                queue.append(i)
                visited[i]=True

cnt = 0
for j in range(1,n+1):
    if visited[j]==False:
        bfs(j)
        cnt+=1
print(cnt)