Accepted Java Solution(15ms) Easy

  • 2

    All you need to do is parse out the alphanumeric characters using StringBuilder then perform a regular palindrome search.

    public class Solution {
        public boolean isPalindrome(String s) {
            if(s == null || s.isEmpty()) return true;
            //Parsing lowercase alphanumeric chars
            StringBuilder sb = new StringBuilder();
            for(char c: s.toLowerCase().toCharArray()){
                if(Character.isLetter(c) || Character.isDigit(c)) sb.append(c);
            //Performing regular palindrome search
            int i = 0, j = sb.length()-1;
            while(i <= j){
                if(sb.charAt(i++) != sb.charAt(j--)) return false;
            return true;

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