Reverse Singly Linked List

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

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Problem

In Snowflake-style coding interviews, a common data structure task is to reverse a singly linked list in place. Write a function that takes the head of a singly linked list and returns the head of the reversed list.

Formal Specification

Input: head, the first node of a singly linked list, or null for an empty list.
Output: The new head node after reversing the list.
Each node has two fields: val and next.
You must reverse the links between nodes rather than creating a new list of copied nodes.

Constraints

0 <= number of nodes <= 5000
-10^4 <= Node.val <= 10^4
Each node contains val and next
Do not allocate a copied list for the main solution

Function Signature

def reverse_linked_list(head):

Your solutionPython 3

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