题解 | 走迷宫

from collections import deque

n,m = list(map(int,input().split()))
xs,ys,xt,yt = map(int,input().split())
xs -= 1
ys -= 1
xt -= 1
yt -= 1
grid = [input() for _ in range(n)]
visit = [[False]*m for _ in range(n)]

dx = [-1, 1, 0, 0]
dy = [0, 0, -1, 1]

q = deque()
q.append((xs,ys))
visit[xs][ys]=True
step = 0
while q:
    size = len(q)

    for _ in range(size):
        x,y = q.popleft()
        if x==xt and y==yt:
            print(step)
            exit()
        
        for  i in range(4):
            nx = x+dx[i]
            ny = y+dy[i]
            if nx>=0 and nx<n and ny>=0 and ny<m:
                if not visit[nx][ny] and grid[nx][ny]=='.':
                    visit[nx][ny]=True
                    q.append((nx,ny))
        
    step += 1
print(-1)