백준 2667 단지번호붙이기

나의 답

import sys
from collections import deque

N = int(sys.stdin.readline())
graph = [[i for i in list(map(int, sys.stdin.readline().rstrip()))] for _ in range(N)]
q = deque()
stack = []
dx = [0, 0, 1, -1]
dy = [1, -1, 0, 0]

def bfs(x, y):
    q = deque([(x, y)])
    graph[x][y] = 0
    cnt = 1
    while q:
        prev_x, prev_y = q.popleft()
        for i in range(4):
            next_x, next_y = prev_x + dx[i], prev_y + dy[i]
            if 0 <= next_x < N and 0 <= next_y < N:
                if graph[next_x][next_y] == 1:
                    q.append((next_x, next_y))
                    graph[next_x][next_y] = 0
                    cnt += 1
    return cnt

for i in range(N):
    for j in range(N):
        if graph[i][j] == 0:
            continue
        else:
            stack.append(bfs(i, j))

print(len(stack))
print(*sorted(stack), sep='\n')