백준 2573. 빙산

https://www.acmicpc.net/problem/2573

2573번: 빙산

def bfs(si,sj):
    q=deque([(si,sj)])
    visited[si][sj] = 1
    while q:
        i, j = q.popleft()
        for ti, tj in [(1, 0), (-1, 0), (0, 1), (0, -1)]:
            ni, nj = i + ti, j + tj
            if 0 <= ni < n and 0 <= nj < m:
                if arr[ni][nj]!= 0 and not visited[ni][nj]:
                    visited[ni][nj] = 1
                    q.append((ni,nj))
                elif arr[ni][nj] == 0:
                    cnt_arr[i][j] += 1
    return 1

import sys
from collections import deque
input = sys.stdin.readline
n, m = map(int,input().split())
arr = [list(map(int,input().split())) for _ in range(n)]

case = 0
while True:
    cnt_arr = [[0]*m for _ in range(n)]
    visited = [[0] * m for _ in range(n)]
    result,flag = 0,0

    for i in range(n):
        for j in range(m):
            if arr[i][j] != 0 and not visited[i][j]:
                result += bfs(i,j)

    for i in range(n):
        for j in range(m):
            arr[i][j] = max(0, arr[i][j] - cnt_arr[i][j]) # 최대 0으로 설정

    if result == 0:
        break
    if result >= 2:
        flag = 1
        break
    case += 1

if flag:
    print(case)
else:
    print(0)