题目简述：

Given an absolute path for a file (Unix-style), simplify it.

For example,

path = "/home/", => "/home"

path = "/a/./b/../../c/", => "/c"

click to show corner cases.

解题思路：

很明显是压栈弹栈的过程，难点在特殊情况要考虑周全，corner cases基本提示全了

class Solution:

    # @param path, a string

    # @return a string

    def simplifyPath(self, path):

        s = path.strip().split('/')

        sta = []

        for i in s:

            if i == '..':

                if len(sta) > 0:

                    sta.pop()

                else:

                    pass

            elif i == '.':

                pass

            elif i == '':

                pass

            else:

                sta.append(i)

        return '/'+'/'.join(sta)

s = Solution()

print s.simplifyPath("//home/")

print s.simplifyPath("/a/./b/../../c/")

print s.simplifyPath("/home/../../..")