题目:
Given a string, determine if it is a palindrome, considering only alphanumeric characters and ignoring cases.
For example,"A man, a plan, a canal: Panama" is a palindrome."race a car" is not a palindrome.
Note:
Have you consider that the string might be empty? This is a good question to ask during an interview.
For the purpose of this problem, we define empty string as valid palindrome.
1 public class Solution { 2 public boolean isPalindrome(String s) 3 { 4 int i = 0; 5 int j = s.length()-1; 6 while(i<j) 7 { 8 while(i<j&&!Character.isLetterOrDigit(s.charAt(i))) i++; 9 while(i<j&&!Character.isLetterOrDigit(s.charAt(j))) j--; 10 if(Character.toLowerCase(s.charAt(i))!=Character.toLowerCase(s.charAt(j)))return false; 11 i++;j--; 12 } 13 14 return true; 15 } 16 }
reference: Clean Code Handbook
原文：http://www.cnblogs.com/hygeia/p/4830949.html