Question

I need this in java using textpad. I am missing a few lines where I added in comments. I don't know what I need to add in. Here are the two programs as pasteable code.The comments in the code say what I need done. The two programs are below. I need it to work with the generic version of SLLNode. It is posted at the bottom.

public class ListDemoHw {

        public static void printLinkedList(SLLNode node) {
                // display all elements in the linked list
                while(node != null) {
                        System.out.print(node.info + " ");
                        node = node.next; // move to the next node
                }       
                System.out.println();
        }
        static SLLNode generateLL1() {
                // Create/return a linked list that has {3, 4, 1, 2}
                // Note that this is not quite a useful function. Just for practice purpose
        }
        static SLLNode generateLL2(int a, int b) {
                // Create/return a linked list that has {a, b, a, b}
                // eg) generateLL2(10,20) returns a list {10,20,10,20}
        }
        static SLLNode generateLL_with_array(int[] nums) {
                // Creat/return a linked list using the given int array
                // Return null if the array is empty (size is zero).
                // eg) generateLL3(new int[]{2,3,4}) returns a list {2,3,4}
        }
        static void attach(SLLNode ls1, SLLNode ls2) {
                // Given two linked lists, attach the second list at the end of the first list
                // eg) Suppose ls1={1,2,3}, ls2={50,60} as lists, attach(ls1, ls2) makes ls1 = {1,2,3,50,60}
                // Assume ls1 is not empty.
                // Hint: You need to go to the last node of ls1 and make a connection from it to the ls2
        }
        public static void main(String[] args) {
                printLinkedList(generateLL1()); // 3 4 1 2
                printLinkedList(generateLL2(20,30)); // 20 30 20 30
                printLinkedList(generateLL_with_array(new int[] {2})); // 2
                printLinkedList(generateLL_with_array(new int[] {2,3,4,5})); // 2 3 4 5
                SLLNode ls1 = generateLL1();
                attach(ls1,generateLL2(20,30));
                printLinkedList(ls1); // 3 4 1 2 20 30 20 30
        }
}

---------------------------------------------------------------------------------------------------

public class SLLNode<E> {
        E info;
        SLLNode<E> next;
        public SLLNode(E val) {
                info = val;
                next = null;
        }
}

Answer 1

Solution:

ListDemoHw.java

public class ListDemoHw {

    public static void printLinkedList(SLLNode node) {
        // display all elements in the linked list
        while (node != null) {
            System.out.print(node.info + " ");
            node = node.next; // move to the next node
        }
        System.out.println();
    }

    static SLLNode generateLL1() {
        // Create/return a linked list that has {3, 4, 1, 2}
        // Note that this is not quite a useful function. Just for practice purpose
        SLLNode head = new SLLNode(3); // 3 at head

        // Nodes for 4, 1, 2
        SLLNode node2 = new SLLNode(4);
        SLLNode node3 = new SLLNode(1);
        SLLNode node4 = new SLLNode(2);

        // Connect nodes
        head.next = node2;
        node2.next = node3;
        node3.next = node4;

        return head;
    }

    static SLLNode generateLL2(int a, int b) {
        // Create/return a linked list that has {a, b, a, b}
        // eg) generateLL2(10,20) returns a list {10,20,10,20}
        int[] nums = { a, b, a, b };
        return generateLL_with_array(nums);
    }

    static SLLNode generateLL_with_array(int[] nums) {
        // Create/return a linked list using the given int array
        // Return null if the array is empty (size is zero).
        // eg) generateLL3(new int[]{2,3,4}) returns a list {2,3,4}

        // Head
        SLLNode head = new SLLNode(nums[0]);

        SLLNode temp = head; // temp at head
        for (int i = 1; i < nums.length; i++) {
            SLLNode newNode = new SLLNode(nums[i]); // new node
            temp.next = newNode; // connecting newnode to temp
            temp = newNode; // changing temp
        }

        return head;
    }

    static void attach(SLLNode ls1, SLLNode ls2) {
        // Given two linked lists, attach the second list at the end of the first list
        // eg) Suppose ls1={1,2,3}, ls2={50,60} as lists, attach(ls1, ls2) makes ls1=
        // {1,2,3,50,60}
        // Assume ls1 is not empty.
        // Hint: You need to go to the last node of ls1 and make a connection from it to
        // the ls2

        // Get the tail of first linked list
        SLLNode temp = ls1;
        while (temp.next != null) {
            temp = temp.next;
        }

        // Connect tail of ls1 with head of ls2
        temp.next = ls2;
    }

    public static void main(String[] args) {
        printLinkedList(generateLL1()); // 3 4 1 2
        printLinkedList(generateLL2(20, 30)); // 20 30 20 30
        printLinkedList(generateLL_with_array(new int[] { 2 })); // 2
        printLinkedList(generateLL_with_array(new int[] { 2, 3, 4, 5 })); // 2 3 4 5
        SLLNode ls1 = generateLL1();
        attach(ls1, generateLL2(20, 30));
        printLinkedList(ls1); // 3 4 1 2 20 30 20 30
    }
}

SLLNode.java

public class SLLNode<E> {
  E info;
  SLLNode<E> next;

  public SLLNode(E val) {
    info = val;
    next = null;
  }
}

Output:

Screenshots: