https://programmers.co.kr/learn/courses/30/lessons/43162?language=python3
def dfs(x, n, computers, visited):
visited[x] = True
for i in range(n):
if computers[x][i] == 1 and x != i:
if visited[i] == False:
dfs(i, n, computers, visited)
def solution(n, computers):
answer = 0
visited = [False for _ in range(n)]
for i in range(n):
if visited[i] == False:
answer += 1
dfs(i, n, computers, visited)
return answer