leetcode206 反转链表 两种做法（循环，递归）

Posted 2022-06-06 wmxl

反转链表 leetcode206

方法1 循环
···
public ListNode reverseList(ListNode head)
if (head == null || head.next == null)
return head;

ListNode now = head;
while (now.next != null)
ListNode temp = now.next;
now.next = now.next.next;
temp.next = head;
head = temp;

return head;
···
方法2 递归
public ListNode reverseList2(ListNode head) if (head == null || head.next == null) return head; ListNode newHead = reverseList2(head.next); ListNode now =newHead; while (now.next != null) now = now.next; now.next = head; head.next = null; return newHead;