Linked Lists
Write a function that takes the head node of a linked list and returns the head of a new linked list, where the nodes are in the reverse order.
For example, given this list:
return this list:
We’ve provided a Node class with a helper method for printing that node and all following nodes (this is used by our tests and is useful for debugging):
class Node(object):
"""Class in a linked list."""
def __init__(self, data, next=None):
self.data = data
self.next = next
def as_string(self):
"""Represent data for this node and it's successors as a string.
>>> Node(3).as_string()
'3'
>>> Node(3, Node(2, Node(1))).as_string()
'321'
"""
out = []
n = self
while n:
out.append(str(n.data))
n = n.next
return "".join(out)
We’ve also provided the start of a reverse_linked_list function:
def reverse_linked_list(head):
"""Given LL head node, return head node of new, reversed linked list.
>>> ll = Node(1, Node(2, Node(3)))
>>> reverse_linked_list(ll).as_string()
'321'
"""
It should work like this:
>>> ll = Node(1, Node(2, Node(3)))
>>> new_ll = reverse_linked_list(ll)
>>> new_ll.as_string()
'321'
Complete this function.