演算法描述：給定開始點座標(x,y) 和終點座標(p,q)，在一個二維數組裡面，其中1代表障礙物，0則沒有。求開始到終點的最短距離。

程式碼如下：

MIN = 9999999

a = [[0 for col in range(50)] for row in range(50)]#迷宮最大陣列
book = [[0 for col in range(50)] for row in range(50)]#標記陣列

def dfs(start_x,start_y,end_x,end_y,migong_array,step):
    '''
    :param start_x: 起始橫座標
    :param start_y: 起始縱座標
    :param end_x: 終點橫座標
    :param end_y: 終點縱座標
    :param migong_array: 迷宮的陣列
    :return:
    '''
 

    next_step = [[0,1],  #向右走
            [1,0],  #向下走
            [0,-1], #向左走
            [-1,0]  #向上走
            ]
    if (start_x == end_x and start_y == end_y):
        global MIN
        if(step < MIN):
            MIN = step
        return

    for i in range(len(next_step)):
        next_x = start_x + next_step[i][0
 
]
        next_y = start_y + next_step[i][1]

        if(next_x < 0 or next_y < 0 or next_x > len(migong_array) or next_y > len(migong_array[0])):
            continue
        if(a[next_x][next_y] == 0 and book[next_x][next_y] == 0):
            book[next_x][next_y] = 1
            dfs(next_x,next_y,end_x,end_y,migong_array,step+1
 
)
            book[next_x][next_y] = 0
    return

if __name__ == '__main__':
    start_x = 0
    start_y = 0
    end_x = 3
    end_y = 2
    migong_array = [[0,0,1,0],[0,0,0,0],[0,0,1,0],[0,1,0,0],[0,0,0,1]]   #初始化迷宮

    for i in range(len(migong_array)):
        for j in range(len(migong_array[0])):
            a[i][j] = migong_array[i][j]  #將迷宮陣列寫入a中
    book[start_x][start_y] = 1  #將第一步標記為1，證明走過了。避免重複走

    dfs(start_x,start_y,end_x,end_y,migong_array,0)

    print('The min length of path is : {}'.format(MIN)) #輸出為7，即最短路徑為 7