Copy List with Random Pointer

A linked list is given such that each node contains an additional random pointer which could point to any node in the list or null.

Return a deep copy of the list.

see comments

public RandomListNode copyRandomList(RandomListNode head) {
        if (head==null) {
            return head;
        }

        RandomListNode current = head;
        //1.insert the copy of nth node between original nth and (n+1)th
        while (current!=null) {
            RandomListNode next = current.next;
            RandomListNode copy = new RandomListNode(current.label);
            current.next = copy;
            copy.next = next;
            current = next;
        }

        //2. set the random pointer for each copy node
        current = head;
        RandomListNode newHead = current.next;
        while (current!=null) {
            if (current.random!=null) {
                //copy.random.next should also point to a copy node
                current.next.random = current.random.next;
            }
            current = current.next.next;
        }

        //3. recover the original node and copy node
        current = head;
        while (current!=null) {
            RandomListNode next = current.next.next;
            RandomListNode copy = current.next;
            current.next = next;
            if (copy.next!=null) {
                copy.next = copy.next.next;
            }           
            current = next;
        }

        return newHead;
    }