运用栈简化路径

#
# 
# @param path string字符串 
# @return string字符串
#
class Solution:
    def simplifyPath(self , path ):
        # write code here
        stack=[]
        parts = path.split('/')
        for part in parts:
            if part == '..' :
                if stack:
                    stack.pop()
            elif part =='.'or part == '':
                continue
            else:
                stack.append(part)
        return '/'+'/'.join(stack)