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.

RandomListNode* result;
        if (!head) return result;
        
        // copy each node in the original list
        RandomListNode* move = head;
        while (move) {
            RandomListNode* temp = new RandomListNode(move->label);
            temp->next = move->next;
            move->next = temp;
            move = move->next->next;
        }
        
        // specify the random pointer of each new node
        move = head;
        while (move) {
            if (move->random) 
                move->next->random = move->random->next;
            move = move->next->next;
        }
        
        // break the list into two and return the new one
        move = head;
        RandomListNode* newHead = head->next;
        RandomListNode* moveNew = newHead;
        while (move) {
            move->next = move->next ? move->next->next : NULL;
            moveNew->next = moveNew->next ? moveNew->next->next : NULL;
            move = move->next;
            moveNew = moveNew->next;
        }
        
        return newHead;