Scamming the coding interview : Problem 015 : Reverse the linked list

reverse_linked_list.py

"""
Scamming the coding interview. Problem 015

Subscribe to our newsletter at https://scammingthecodinginterview.com/
to get a coding or design problem daily in your inbox and become exceptionally good at
coding interviews.
"""


class Node(object):

    def __init__(self, value):
        self.value = value
        self.next = None


def reverse_linked_list(head):

    temp_head = head

    if not head:
        return head

    prev = head
    curr = head.next

    while curr:

        next = curr.next
        curr.next = prev
        prev = curr
        curr = next

    temp_head.next = None

    return prev


def print_linked_list(head):
    value = ""
    while head:
        value += (str(head.value) + "->")
        head = head.next

    print(value)


if __name__ == '__main__':

    head = Node(1)
    node_2 = Node(2)
    node_3 = Node(3)
    node_4 = Node(4)

    head.next = node_2
    node_2.next = node_3
    node_3.next = node_4

    print_linked_list(head)

    head = reverse_linked_list(head)

    print_linked_list(head)