4
next = null
null
2. current.next = prev;
2. current.next = prev;
1
4. current = next;
指针
3
1. next = current.next;
next
2
3. prev = current;
current
prev
4. current = next;
按照红色虚线可以得到下面的结果
5
head
最终prev指向的就是新的链表表头
重新建立的链接
3. prev = current;
1. next = current.next;
prev = null
current = head
需要断开的链接
