Reverse Linked List In Place | Dataford Interview Questions

Reverse a linked list in place.

Asked in the round 1 stage. Implement the function below for a singly linked list. Return the new head after reversing the existing nodes; do not create replacement nodes.

Input and Output

head is either None or a ListNode with value and next fields. Return the new head. The test cases represent lists as arrays of node values.

Constraints

0 <= number of nodes <= 10^5
Node values are integers
The input is a singly linked list
Reverse the existing nodes without allocating replacement nodes
Use O(1) auxiliary space

Function Signature

def reverse_list(head):

Your question is Reverse Linked List In Place. Start with the requirements in the Question tab.

Run and submit as often as you like. When you're ready, talk me through your approach or go straight to the code.

Problem