1 public class Solution {
 2         public boolean isPalindrome(String s) {
 3             if(s.length()<=1) return true;
 4             s = s.toLowerCase();
 5             int start = 0;
 6             int end = s.length()-1;
 7             while(start<end){
 8                 if(!is(s.charAt(start))) start++;
 9                 else if(!is(s.charAt(end))) end --;
10                 else if(s.charAt(start)==s.charAt(end)){start++;end--;}
11                 else break;
12             }
13             if(start>=end) return true;
14             else return false;
15         }
16         public boolean is(char a){
17             if(a<=‘z‘&& a>=‘a‘ || a>=‘0‘&&a<=‘9‘){
18                 return true;
19             }
20             else return false;
21         }
22     }