Simplify_Path

# author: marissazhou
# date: 30/08/2014
# idea: look through all strings between '/' and check sign

class Solution:
    # @param path, a string
    # @return a string
    def simplifyPath(self, path):
        if path is None:
            return
        if len(path)<2:
            return path
        stack = []
        i = 1
        while i < len(path):
            sstr = ''
            while i<len(path) and path[i] is not "/":
                sstr = sstr + path[i]
                i = i+1
            if sstr == "..":
                if len(stack) > 0:
                    stack.pop()
            elif sstr == ".":
                continue
            elif len(sstr)>0:
                stack.append(sstr)
            if i<len(path) and path[i] == '/':
                i = i+1
                continue
        # reunion
        if len(stack) == 0:
            return '/'
        result = ''
        for i in xrange(len(stack)):
            result = result+"/"+stack[i]
        return result