leetcode:Valid Palindrome

 1 class Solution:
 2     # @param s, a string
 3     # @return a boolean
 4     def isPalindrome(self, s):
 5         ret = False
 6         s = s.lower()
 7         ss = ""
 8         for i in s:
 9             if i.isalnum():
10                 ss += i
11         h = 0
12         e = len(ss)-1
13         while(h<e):
14             if(ss[h] == ss[e]):
15                 h += 1
16                 e -= 1
17             else:
18                 break
19         if h>=e:
20             ret = True
21         return ret