LeetCode #125. Valide Palindrome

Time Complexity O(n)

Space Complexity O(n)

class Solution {
    public boolean isPalindrome(String s) {

        s = s.replaceAll("[^a-zA-Z0-9]", "").toLowerCase();

        int left = 0;
        int right = s.length() - 1;

        while(left < right) {
            if (s.charAt(left) != s.charAt(right))
                return false;
            left++;
            right--;
        }
        return true;
    }
}