注意的点:
这道题三番五次地做错,总是想着交换首尾链表的位置,其实正确的做法就是从头到尾两两交换链表的指针方向即可。
解法:双指针
class Solution:
def reverseList(self, head: Optional[ListNode]) -> Optional[ListNode]:
fast, slow = head, None
while fast:
temp = fast.next
fast.next = slow
slow = fast
fast = temp
return slow