迷宫BFS

def solve(____):
    from collections import deque
    maze = [list(____) for row in maze.split(____)]
    m, n = len(____), len(____)
    directions = [(____, ____), (____, ____), (____, -____), (____)]
    queue = deque([(____, ____, ____)])
    visited = {(____, ____)}
    while queue:
        r, c, dist = queue.popleft()
        if r == m - ____ and c == n - ____:
            print(____)
            return
        for dr, dc in directions:
            nr, nc = r + dr, c + dc
            if ____ <= nr < m and ____ <= nc < n and maze[nr][nc] == '____' and (____) not in visited:
                visited.add((____))
                queue.append((____))
    print(____)