class Solution {
    public void merge(int[] nums1, int m, int[] nums2, int n) {
        if (n == 0) return;

        int last = n + m - 1;
        m = m - 1;
        n = n - 1;

        while (n >= 0) {
            if (m >= 0 && nums1[m] > nums2[n]) {
                nums1[last--] = nums1[m--];
            } else {
                nums1[last--] = nums2[n--];
            }
        }
    }
}

    public boolean isPalindrome(String s) {
        int left = 0;
        int right = s.length() - 1;

        while (left < right) {
            while (left < right && !Character.isLetterOrDigit(s.charAt(left))) {
                left += 1;
            }

            while (left < right && !Character.isLetterOrDigit(s.charAt(right))) {
                right -= 1;
            }

            char leftChar = Character.toLowerCase(s.charAt(left));
            char rightChar = Character.toLowerCase(s.charAt(right));
            if (leftChar != rightChar) {
                return false;
            }

            left += 1;
            right -= 1;
        }

        return true;
    }