数据结构：迷宫问题（三）

一、栈的应用——迷宫问题

1、解题思路

2、实现代码

import time
from collections import deque

maze = [
    [1,1,1,1,1,1,1,1,1,1],
    [1,0,0,1,0,0,0,1,0,1],
    [1,0,0,1,0,0,0,1,0,1],
    [1,0,0,0,0,1,1,0,0,1],
    [1,0,1,1,1,0,0,0,0,1],
    [1,0,0,0,1,0,0,0,0,1],
    [1,0,1,0,0,0,1,0,0,1],
    [1,0,1,1,1,0,1,1,0,1],
    [1,1,0,0,0,0,0,1,0,1],
    [1,1,1,1,1,1,1,1,1,1]
]

dirs = [lambda x, y: (x + 1, y),
        lambda x, y: (x - 1, y),
        lambda x, y: (x, y - 1),
        lambda x, y: (x, y + 1)]

def mpath(x1, y1, x2, y2):
    stack = []
    stack.append((x1, y1))
    while len(stack) > 0:   #当栈不空循环
        cur_node = stack[-1]
        if cur_node[0] == (x2,y2):  #到达终点
            for p in stack:
                print(p)
            return True
        for dir in dirs:
            next_node = dir(*cur_node)
            if maze[next_node[0]][next_node[1]] == 0:  #找到了一个能走的方向
                stack.append(next_node)
                maze[next_node[0]][next_node[1]] = 2  # 2标记为已经走过，防止死循环
                break
        else:#如果一个方向都没找到
            maze[curNode[0]][curNode[1]] = -1  # 死路一条,下次别走了
            stack.pop() #回溯
    else:
        print("没有路")
        return False

二、队列的应用——迷宫问题

1、解题思路

2、实现代码

import time
from collections import deque

maze = [
    [1,1,1,1,1,1,1,1,1,1],
    [1,0,0,1,0,0,0,1,0,1],
    [1,0,0,1,0,0,0,1,0,1],
    [1,0,0,0,0,1,1,0,0,1],
    [1,0,1,1,1,0,0,0,0,1],
    [1,0,0,0,1,0,0,0,0,1],
    [1,0,1,0,0,0,1,0,0,1],
    [1,0,1,1,1,0,1,1,0,1],
    [1,1,0,0,0,0,0,1,0,1],
    [1,1,1,1,1,1,1,1,1,1]
]

dirs = [lambda x, y: (x + 1, y),
        lambda x, y: (x - 1, y),
        lambda x, y: (x, y - 1),
        lambda x, y: (x, y + 1)]

def solve_maze2(x1,y1,x2,y2):
    queue = deque()
    path = []  #记入出队之后的节点
    queue.append(x1,y1,-1)
    maze[x1][y1] = 2
    while len(queue) > 0:
        cur_node = queue.popleft()
        path.append(cur_node)
        if cur_node[0] == x2 and cur_node[1] == y2:  #找到终点
            real_path = []
            x,y,i = path[-1]
            real_path.append((x,y))
            while i >= 0:
                node = path[i]
                real_path.append(node[0:2])
                i = node[2]
            real_path.reverse()
            for p in real_path:
                print(p)
            return True
        for dir in dirs:
            next_node =dir(cur_node[0],cur_node[1])
            if maze[next_node[0]][next_node[1]] == 0:
                queue.append(next_node[0],next_node[1],len((path)-1))
                maze[next_node[0]][next_node[1]] = 2 #标记已经走过
    else:
        print("无路可走")
mpath(1,1,8,8)