我试图在 Python 中解决 Ruby Quiz 问题 60，这里给出： http ://rubyquiz.com/quiz60.html
基本上，只需将一个数字加倍、减半或加 2，就必须找到从一个数字到另一个数字的最短路径。
编写一个程序来实际解决这个问题并不太难：
def maze_solver(a, b):
paths = [[a]]
final = []
for ind, path in enumerate(paths):
if path[-1] == b:
return path
last = path[-1]
paths.append(path + [last * 2])
paths.append(path + [last + 2])
if last % 2 == 0:
paths.append(path + [last / 2])
print maze_solver(979, 2)
>>> maze_solver(9, 2)
[9, 18, 20, 10, 12, 6, 8, 4, 2]
>>> maze_solver(2, 9)
[2, 4, 8, 16, 18, 9]
但是当我尝试优化它时，它失败了。我认为如果两条路径具有相同的终点并且一条路径比另一条路径短，那么可以消除较长的路径。
我试过这个优化：
def maze_solver(a, b):
paths = [[a]]
final = []
for ind, path in enumerate(paths):
if path[-1] == b:
return path
for other in paths:
if ind != paths.index(other):
if path[-1] == other[-1] and len(other) >= len(path):
paths.remove(other)
last = path[-1]
paths.append(path + [last * 2])
paths.append(path + [last + 2])
if last % 2 == 0:
paths.append(path + [last / 2])
但这甚至不能产生正确的答案：
>>> maze_solver(9, 2)
[9, 11, 22, 24, 48, 24, 12, 6, 8, 4, 2]
我不知道为什么这段代码不起作用，所以如果有人能向我解释我做错了什么，那将非常有帮助，谢谢！