public static int unsortedAt(int[] a) {
        for (int i = 1; i < a.length; i++)
            if (a[i] < a[i - 1])
                return i - 1;
        return -1;
    }

    public static void swap(int[] a, int i) {
        int temp = a[i + 1];
        a[i + 1] = a[i];
        a[i] = temp;
    }

    public static void sort(int[] a) {
        int i = unsortedAt(a);
        while (i != -1) {
            swap(a, i);
            i = unsortedAt(a);
        }
    }

    public static int spiderman(int n) {
        if (n == 0 || n == 1)
            return 1;
        return spiderman(n - 1) + spiderman(n - 2);
    }

    public static void printBinary(int n) {
        String s = new String();
        s = getBinary(n, s);
        for (int i = s.length() - 1; i >= 0; i--) {
            System.out.print(s.charAt(i));
        }
    }

    public static String getBinary(int n, String s) {
        if (n != 0) {
            s += n % 2;
            return getBinary(n / 2, s);
        } else
            return s;
    }

    public static boolean isPalindrome(String s) {
        for (int i = 0; i < s.length() / 2; i++)
            if (s.charAt(i) != s.charAt(s.length() - 1 - i))
                return false;
        return true;
    }