Reverse a Linked List

EasyPython

Problem

Solve a problem related to data structures, such as reversing a linked list.

Implement reverse_linked_list(head) for a singly linked list. Each node has val and next fields. Return the new head after reversing all links in place. The input and output are linked-list nodes, not arrays; array forms in the examples and tests represent serialized lists.

Constraints

The list contains 0 to 10^5 nodes.
Each node has a val field and a next field.
Node values may be arbitrary integers.
The reversal must be performed by changing links, not by creating replacement nodes.

Function Signature

def reverse_linked_list(head):

CodePython 3

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