LeetCode 206번 문제

class ListNode:
    def __init__(self, val=0, next=None):
        self.val = val
        self.next = next


class Solution:
    def my_solution(self, head: ListNode) -> ListNode:
        reversed_list = None
        while head:
            reversed_list = ListNode(head.val, reversed_list)
            head = head.next
        return reversed_list

class ListNode:
    def __init__(self, val=0, next=None):
        self.val = val
        self.next = next


class Solution:
    def solution1(self, head: ListNode) -> ListNode:
        def reverse(node: ListNode, prev: ListNode = None):
            if not node:
                return prev
            next, node.next = node.next, prev
            return reverse(next, node)

        return reverse(head)

class ListNode:
    def __init__(self, val=0, next=None):
        self.val = val
        self.next = next


class Solution:
    def solution2(self, head: ListNode) -> ListNode:
        node, prev = head, None

        while node:
            next, node.next = node.next, prev
            prev, node = node, next

        return prev