Reverse Linked List

EasyPython

Problem

Given the head of a singly linked list, reverse the list and return the new head. Implement both an iterative solution and a recursive solution.

Formal Specification

Write a function that accepts the head node of a singly linked list. Each node has two fields: val and next. Return the head node of the reversed list. The list may be empty or contain one node.

You should provide two approaches in your solution: one using iteration and one using recursion.

Constraints

0 <= number of nodes <= 10^5
-10^9 <= Node.val <= 10^9
The input is a singly linked list
The solution should run in linear time

Function Signature

def reverse_list(head):

CodePython 3

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