If we want to enqueue someone, that is, add them to the line, we have to traverse down the linked list until we hit the end, and then change that next pointer to point to the new person.

如果我们想将某人入队，也就是将他们添加到行中，我们必须向下遍历链表直到到达末尾，然后将 next 指针更改为指向新人。