链表转置
Node pre =null;
Node cur = head;
while (cur !=null) {
Node next = cur.next;
cur.next = pre;
pre = cur;
cur = next;
}
head = pre;
利用优先队列排序
创建 PriorityQueue queue =new PriorityQueue<>((o1, o2) -> o2 - o1);
添加 queue.add
取出 queue.poll
获得第一个元素 queue.peek
交换顺序
Collections.swap
