交错2链接列表C ++

Question

我正在开发一个功能，将2个单链表交织在一起（我已经完成了实验室，现在正在我自己的时间进行处理）而且我被卡住了。我已经尝试了很多东西，但我无法弄明白。谁能帮我吗？谢谢！

 /**
 * Create a new linked_list by merging two existing linked_lists.
 * PRE: list1 is the first Node in a linked_list (if NULL, then it is empty)
 * PRE: list2 is the first Node in another linked_list (if NULL, then it is empty)
 * POST: A new linked_list is returned that contains new Nodes with the keys from
 * the Nodes in list1 and list2, starting with the key of the first Node of list1,
 * then the key of the first Node of list2, etc.
 * When one list is exhausted, the remaining keys come from the other list.
 * For example: [1, 2] and [3, 4, 5] would return [1, 3, 2, 4, 5]
 */
Node* interleave(Node* list1, Node* list2){
  if (list1 == NULL && list2 == NULL) { return NULL; }

  Node * p1 = list1;
  Node * p2 = list2;
  Node * newNode = new Node;

  while (list1 != NULL && list2 != NULL) {
    newNode->key = p1->key;
    p1 = p1->next;
    newNode->next->key = p2->key;
    p2 = p2->next;
  }

  if (list1 == NULL && list2 != NULL) {
    while (list2 != NULL) {
      newNode->key = p2->key;
      p2 = p2->next;
    }
  } else if (list2 == NULL && list1 != NULL) {
    while (list1 != NULL) {
      newNode->key = p1->key;
      p1 = p1->next;
    }
  }
  return newNode;
}