地址:https://leetcode-cn.com/problems/reverse-linked-list/
1、循环法
# Definition for singly-linked list.
# class ListNode:
# def __init__(self, val=0, next=None):
# self.val = val
# self.next = next
class Solution:def reverseList(self, head: ListNode) -> ListNode:curr,prev = head,Nonewhile curr:next = curr.nextcurr.next = prevprev = currcurr = nextreturn prev
2、递归法
# Definition for singly-linked list.
# class ListNode:
# def __init__(self, val=0, next=None):
# self.val = val
# self.next = next
class Solution:def reverseList(self, head: ListNode) -> ListNode:if head.next is None or head is None:retun head.nextp = self.reverseList(head.next)head.next.next = headhead.next = Noneretun p
