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