125.valid-palindrome.java

class Solution {
    public boolean isPalindrome(String s) {
             // remove spaces and non numes
        // use 2 pointers to looop through the string
        //i to start from the begining 0 and at the end newS.size-1
        //while i<j
        // compare  char at pointer i if is equal to char at pointer 
        // increament i decrement j, if they meet without a false, then its a palindrome
        // if at any point a we get a false, tehn we terminate and return false
        //string newS = s.replaceAll("[^A-Za-z]+", "").toLowerCase();
        
        //string  newS =s.replaceAll("[^a-zA-Z ]", "").toLowerCase();
       // String newS = s.replaceAll("[^A-Za-z]+", "").toLowerCase();
        String newS = s.replaceAll("[^A-Za-z0-9]+", "").toLowerCase();

        int i = 0;
        int j = newS.length()-1;

        while(i<j){
            if(newS.charAt(i) != newS.charAt(j)){
                return false;
            }
            i++;
            j--;
        }
        return true;
    }
    
    }