# 使用 Python 实现的广度优先搜索实现迷宫算法
class Maze(object):
def __init__(self, maze, start, end):
self.maze = maze
self.start = start
self.end = end
self.direction = [[-1, 0], [0, -1], [1, 0], [0, 1]] # 移动方向顺序: 上左下右
def move(self, x, y):
"""
执行迷宫的上下左右操作
:param x: 起始坐标
:param y: 移动的方向
:return: 新的坐标
"""
return [x[0] + y[0], x[1] + y[1]]
def at(self, grid, x):
"""
传入一个maze和坐标，判断坐标是否越界，如果没有越界根据坐标返回对应maze中的数值
:param grid: maze
:param x: 查找坐标
:return: maze中的数值和状态
"""
# 判断row 是否越界
if x[0] < 0 or x[0] >= len(grid):
return 0, False
# 判断col 是否越界
if x[1] < 0 or x[1] >= len(grid[0]):
return 0, False
return grid[x[0]][x[1]], True
def walk(self):
"""
创建一个新的二维数组，self.maze每走一步，就在这个新的二维数组对应位置上记录行走的步数
:return: 记录了行走步数的二维数组
"""
# 创建一个大小和self.maze一样大小的二维数组，此二维数组中所有的值初始化为0，用来记录行走的步数
steps = [[i * 0 for i in range(len(self.maze[0]))] for j in range(len(self.maze))]
Q = [self.start]
while len(Q) > 0:
index = Q[0]
# 找到出口
if index == self.end:
break
Q = Q[1:]
for d in self.direction:
next = self.move(index, d)
val, ok = self.at(self.maze, next)
# 越界或者撞墙，跳过
if not ok or val == 1:
continue
# 新的二维数组中移动的下一个点如果值不是0的话，说明已经走过这个点，直接跳过
val, ok = self.at(steps, next)
if not ok or val != 0:
continue
# 回到原点
if next == self.start:
continue
# 将steps中每走一步，记录当前的步数
val, ok = self.at(steps, index)
if ok:
steps[next[0]][next[1]] = val + 1
# 每走一步，将此时的位置加入到队列中
Q.append(next)
return steps
def path(self, grid):
"""
根据steps计算最优路径
:param grid: steps迷宫图
:return: 存放路径的列表
"""
last = grid[len(maze) - 1][len(maze[0]) - 1]
lookup_path = [[len(maze) - 1, len(maze[0]) - 1], ]
while last > 0:
last -= 1
index = lookup_path[-1]
for d in self.direction:
next = self.move(index, d)
val, err = self.at(grid, next)
if val == last:
lookup_path.append(next)
break
return lookup_path
if __name__ == '__main__':
# maze = [[0, 0, 1, 0, 1], [1, 0, 0, 0, 1], [0, 0, 1, 1, 0], [0, 1, 0, 0, 0], [0, 0, 0, 1, 0]]
maze = [[0, 1, 0, 0, 0], [0, 0, 0, 1, 0], [0, 1, 0, 1, 0], [1, 1, 1, 0, 0], [0, 1, 0, 0, 1], [0, 1, 0, 0, 0]]
# 打印二维数组
print("原始迷宫图:")
for k in maze:
for v in k:
print("%2d" % v, end=" ")
print("")
print("\n")
print("行走路线图:")
step = Maze(maze, [0, 0], [len(maze) - 1, len(maze[0]) - 1])
steps = step.walk()
for k in steps:
for v in k:
print("%2d" % v, end=" ")
print("")
print("\n")
print("走出迷宫共需要%s步\n" % steps[len(maze) - 1][len(maze[0]) - 1])
# 计算最优路径
path = step.path(steps)
path.reverse()
print("最优路径是: ", path)