ylab 2022. 2. 15. 17:03
출처: 이코테 
머리가 아프다 너무 어렵다
 
from collections import deque

n,m = map(int,input().split())

graph = []

for i in range(n):
    graph.append(list(map(int,input())))
#방향벡터 설정
dx = [-1,1,0,0]
dy = [0,0,-1,1]

def bfs(x,y):
    queue = deque()
    queue.append((x,y))
    while queue:
        x, y = queue.popleft()
        for i in range(4):
            nx = x+dx[i]
            ny = y+dy[i]

            if nx<0 or ny<0 or nx>=n or ny>=m:
                continue
            if graph[nx][ny] ==1:
                graph[nx][ny] = graph[x][y]+1
                queue.append((nx,ny))

    return graph[n-1][m-1]


print(bfs(0,0))