LeetCode-Solution-Java/125. Valid Palindrome at main · rising0raj/LeetCode-Solution-Java · GitHub

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Runtime    2 ms
Beats      99.37%


Memory     41.8 MB
Beats      82.69%


class Solution {
    public boolean isPalindrome(String s) {
        if (s.isEmpty()) {
            return true;
        }

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

        while (left < right) {
            char leftChar = s.charAt(left);
            char rightChar = s.charAt(right);

            if (!Character.isLetterOrDigit(leftChar)) {
                left++;
            } else if (!Character.isLetterOrDigit(rightChar)) {
                right--;
            } else {
                if (Character.toLowerCase(leftChar) != Character.toLowerCase(rightChar)) {
                    return false;
                }
                left++;
                right--;
            }
        }

        return true;
    }
}