Question

Write a java to find the Hailstone Sequence of a given number upto 1 using recursion. Example: The hailstone sequence starting at 13 is : 13 40 20 10 5 16 8 4 2 1 The length of the sequence is 10.

Answer 1

import java.util.Scanner;

public class HailstoneSequence {

    public static int hailstone(int n) {
        if (n == 1) {
            System.out.println("1");
            return 1;
        } else {
            System.out.print(n + " ");
            if (n % 2 == 0)
                return 1 + hailstone(n / 2);
            else
                return 1 + hailstone(3 * n + 1);
        }
    }

    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        System.out.print("Enter a positive integer: ");
        int n = in.nextInt();
        System.out.print("Hailstone sequence starting with " + n + " is: ");
        int len = hailstone(n);
        System.out.println("Length of the hailstone sequence starting with " + n + " is " + len);
    }
}