# [leetcode] 206. Reverse Linked List _ Algorithm Problem Solve for python

## 1. Problem

Given the head of a singly linked list, reverse the list, and return the reversed list.

Example 1:

Input: head = [1,2,3,4,5]
Output: [5,4,3,2,1]


Example 2:

Input: head = [1,2]
Output: [2,1]


Example 3:

Input: head = []
Output: []


Constraints:

• The number of nodes in the list is the range [0, 5000].
• -5000 <= Node.val <= 5000

## 2. Solution

I solved this problem like this. Push all node in stack and make new linked list.

# 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: Optional[ListNode]) -> Optional[ListNode]:
stack = []
while node:
stack.append(node)
node = node.next
stack[-1].next = None

stack.pop()
while stack:
node.next = stack[-1]
node = node.next
stack.pop()



Other solution is like this. This solution is simple and easy to understand.

def reverseList(self, head):
new_list = None