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Reverse Linked List

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Your question is Reverse Linked List. Start with the requirements on the right.

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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):
Your solutionPython 3
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