clone linkedlist with random pointers done (optimization pending)

Author: Ram swaroop

src/me/ramswaroop/common/DoubleLinkedList.java

@@ -188,12 +188,12 @@ public void printList() {
         }
         out.println(curr.item + "]");
         // prints the list from last node
-        /*out.print("[");
+        out.print("[");
         while (curr.prev != null) {
             out.print(curr.item + ",");
             curr = curr.prev;
         }
-        out.println(curr.item + "]");*/
+        out.println(curr.item + "]");
     }
 
     public static <E extends Comparable<E>> DoubleLinkedList<E> getLinkedList(DoubleLinkedNode<E> node) {

src/me/ramswaroop/linkedlists/CloneWithRandPointers.java

@@ -15,33 +15,31 @@ public class CloneWithRandPointers<E extends Comparable<E>> extends DoubleLinked
     public static <E extends Comparable<E>> DoubleLinkedList<E> clone(DoubleLinkedNode<E> node) {
         DoubleLinkedNode<E> curr = node;
 
-        // copy node and insert after it
-        while (curr != null && curr.next != null) {
+        // copy each node and insert after it
+        while (curr != null) {
             DoubleLinkedNode<E> newNode = new DoubleLinkedNode<>(null, curr.item, curr.next);
             curr.next = newNode;
             curr = curr.next.next;
         }
 
+        // copy all random pointers from original node to the copied node
         curr = node;
-
-        // copy all random pointers
         while (curr != null && curr.next != null) {
-            curr.next.prev = curr.prev;
+            curr.next.prev = (curr.prev != null) ? curr.prev.next : null;
             curr = curr.next.next;
         }
 
+        // separate the copied nodes into a different linked list
         curr = node;
         DoubleLinkedNode<E> cloneHead = node.next;
-        DoubleLinkedNode<E> dupNode;
-        // separate the copy nodes into a different linked list
-        while (curr != null) {
+        DoubleLinkedNode<E> dupNode = cloneHead;
+        while (curr != null && curr.next != null) {
             dupNode = curr.next;
             curr.next = (dupNode != null) ? dupNode.next : null;
-            if (dupNode != null) {
-                dupNode.next = (curr.next != null) ? curr.next.next : null;
-            }
+            dupNode.next = (curr.next != null) ? curr.next.next : null;
             curr = curr.next;
         }
+
         return DoubleLinkedList.getLinkedList(cloneHead);
     }
 
@@ -51,13 +49,14 @@ public static void main(String a[]) {
         linkedList.add(11);
         linkedList.add(22);
         linkedList.add(33);
-        linkedList.getNode(0).prev = linkedList.getNode(2);
-        linkedList.getNode(1).prev = linkedList.getNode(3);
+        linkedList.getNode(0).prev = null;
+        linkedList.getNode(1).prev = linkedList.getNode(2);
         linkedList.getNode(2).prev = linkedList.getNode(0);
         linkedList.getNode(3).prev = linkedList.getNode(1);
         linkedList.printList();
         DoubleLinkedList<Integer> clonedList = clone(linkedList.getNode(0));
         clonedList.size = 4;
+        clonedList.set(0, 234);
         clonedList.set(1, 567);
         clonedList.printList();
         linkedList.printList();