python 广度优先搜索找最短路径

只有一条路径走得通为什么还要说求最短路径，而且只有一条路径走得通也让大家可以投机取巧，不用广度、深度优先搜索就能出结果（看已通过的代码）；
附上广度优先搜索找最短路径代码（适用真正的多路径找最短问题）：

def bfs(maze,x1,y1,x2,y2):
    directions = [(1,0),(-1,0),(0,1),(0,-1)]
    queue = [(x1,y1,-1)]
    path = []
    while queue:
        path.append(queue.pop(0))
        cur = (path[-1][0],path[-1][1])
        if cur == (x2,y2):
            res = [(path[-1][0],path[-1][1])]
            loc = path[-1][2]
            while loc != -1:
                res.append((path[loc][0],path[loc][1]))
                loc = path[loc][2]
            return res

        for d in directions:
            next_node = (cur[0]+d[0],cur[1]+d[1])
            if 0 <= next_node[0] < len(maze) and \
               0 <= next_node[1] < len(maze[0]) and \
               maze[next_node[0]][next_node[1]] == 0:
                maze[next_node[0]][next_node[1]] == 2
                queue.append((next_node[0],next_node[1],len(path)-1))
while True:
    try:
        m,n = list(map(int, input().split()))
        maze = []
        for i in range(m):
            maze.append(list(map(int, input().split())))
        res = bfs(maze, 0, 0, m-1, n-1)[::-1]
        for i in res:
            print('(%d,%d)'%(i[0],i[1]))
    except:
        break