[Leetcode][JAVA] Valid Palindrome

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。。

     public boolean isPalindrome(String s) {

         int i=0;

         int j=s.length()-1;

         while(i<j) {

             if(!Character.isLetterOrDigit(s.charAt(i))) {

                 i++;

                 continue;

             }

             if(!Character.isLetterOrDigit(s.charAt(j))) {

                 j--;

                 continue;

             }

             if(Character.toLowerCase(s.charAt(i))!=Character.toLowerCase(s.charAt(j)))

                 return false;

             i++;

             j--;

         }

         return true;

     }