java单链表 指针 反转示意图
参考：https://blog.****.net/guyuealian/article/details/51119499
//链表反转
public void Reverse() {
Node pReverse = head;
Node cur = head;
Node pre = null;
while (cur != null) {
Node temp = cur.next;
if (temp == null) {
pReverse = cur;
}
//在改变指针所指的方向
cur.next = pre;
pre = cur;
cur = temp;
}
this.head = pReverse;
}