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.
应该算是leetcode上最简单的题之一了吧。双指针可搞定。。
1 public boolean isPalindrome(String s) { 2 int i=0; 3 int j=s.length()-1; 4 while(i<j) { 5 if(!Character.isLetterOrDigit(s.charAt(i))) { 6 i++; 7 continue; 8 } 9 if(!Character.isLetterOrDigit(s.charAt(j))) { 10 j--; 11 continue; 12 } 13 if(Character.toLowerCase(s.charAt(i))!=Character.toLowerCase(s.charAt(j))) 14 return false; 15 i++; 16 j--; 17 } 18 return true; 19 }
[Leetcode][JAVA] Valid Palindrome
原文：http://www.cnblogs.com/splash/p/4107113.html