백준 - 2638 : 치즈 (G3)

 1from collections import deque
 2
 3dx = [0, 0, -1, 1]
 4dy = [-1, 1, 0, 0]
 5
 6N, M = map(int, input().split())
 7L = [list(map(int, input().split())) for _ in range(N)]
 8
 9def check():
10    q = deque()
11    q.append((0, 0))
12
13    visited = [[0]*M for _ in range(N)]
14    visited[0][0] = 1
15
16    while q:
17        curX, curY = q.popleft()
18
19        for i in range(4):
20            nX = curX + dx[i]
21            nY = curY + dy[i]
22
23            if 0 <= nX < N and 0 <= nY < M:
24                if L[nX][nY] == 0 and visited[nX][nY] == 0:
25                    q.append((nX, nY))
26                    visited[nX][nY] = 1
27                elif L[nX][nY] == 1:
28                    visited[nX][nY] += 1
29    melted = []
30    for i in range(N):
31        for j in range(M):
32            if visited[i][j] >= 2:
33                melted.append((i, j))
34
35    return melted
36
37result = 0
38
39while True:
40    isAnyCheese = False
41
42    melted = check()
43
44    if not melted:
45        break
46
47    for x, y in melted:
48        L[x][y] = 0
49
50    result += 1
51
52print (result)