[算法-单链表反转]

signly_linked_reverse.py

# Definition for singly-linked list.
# class ListNode:
#     def __init__(self, x):
#         self.val = x
#         self.next = None

class Solution:
    def reverseList(self, head: ListNode) -> ListNode:
        prev = None
        current = head
        # 遍历链表
        while current:
            # 记录当前结点的下一结点,同时将当前结点指向 prev
            tmp, current.next = current.next, prev
            # prev 和 current 结点都前进一位
            prev, current = current, tmp
        return prev