public class Solution {

public boolean isPalindrome(String s) {

int left = 0;

int right = s.length() - 1;

while(left < right) {

while(!Character.isLetterOrDigit(s.charAt(left)) && left < right) left++;

while(!Character.isLetterOrDigit(s.charAt(right)) && right > left) right--;

if(Character.toLowerCase(s.charAt(left)) != Character.toLowerCase(s.charAt(right))) return false;

left++;

right--;

}

return true;

}

}