[백준] 11724번_연결요소의개수

문제 링크 : https://www.acmicpc.net/problem/11724

11724번: 연결 요소의 개수

from sys import stdin,stdout
from collections import deque
N,M = map(int,stdin.readline().split())
a = [[] for _ in range(N+1)]
for _ in range(M):
    u,v = map(int,stdin.readline().split())
    a[u].append(v)
    a[v].append(u)

check = [False for _ in range(N+1)]
check[0] = True  
queue = deque()
def bfs(x):
    check[x] = True
    queue.append(x)
    while queue:
        x = queue.popleft()
        for i in range(len(a[x])):
            y = a[x][i]
            if not check[y]:
                check[y] = True
                queue.append(y)
cnt = 0
for i in range(N+1):
    if not check[i]:
        bfs(i)
        cnt+=1
stdout.write(str(cnt))