206. Reverse Linked List
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
Follow up: A linked list can be reversed either iteratively or recursively. Could you implement both?
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1# Definition for singly-linked list.
2# class ListNode:
3# def __init__(self, val=0, next=None):
4# self.val = val
5# self.next = next
6class Solution:
7 def reverseList(self, head: Optional[ListNode]) -> Optional[ListNode]:
8
Starter codePython 3Spaces: 4
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1# Definition for singly-linked list.
2# class ListNode:
3# def __init__(self, val=0, next=None):
4# self.val = val
5# self.next = next
6class Solution:
7 def reverseList(self, head: Optional[ListNode]) -> Optional[ListNode]:
8
Starter codePython 3Spaces: 4
Examples
Input
[1,2,3,4,5]
Input
[1,2]
Input
[]
Your code is saved on this device.Solution