How can I write a recursive function to reverse a linked list?

Question

I am looking to do it with Python. And I don\'t want to just print it in reverse, but actually reverse the given nodes. I have seen it done in other languages but had trouble fi

Answer 1

Slight modification to @Rajat Bhatt implementation. Difference is below code can be executed as a separate function outside of linked list class.

print '\n-- Initialize --'
lst = LinkedList(10)    # 10 --> *
print '\n-- Insert --'
lst.append(20)          # 10 --> 20 --> *
lst.append(30)          # 10 --> 20 --> 30 --> *
lst.insertAt(15, pos=1) # 10 --> 15 --> 20 --> 30 --> *
lst.insertAt(25, pos=3) # 10 --> 15 --> 20 --> 25 --> 30 --> *
lst.insertAt(2)         # 2 --> 10 --> 15 --> 20 --> 25 --> 30 --> *
lst.append(100)         # 2 --> 10 --> 15 --> 20 --> 25 --> 30 --> 100 --> *
lst.append(500)         # 2 --> 10 --> 15 --> 20 --> 25 --> 30 --> 100 --> 500 --> *


print lst
# 2 --> 10 --> 15 --> 20 --> 25 --> 30 --> 100 --> 500 --> *

print '\n-- Reverse using Recursion --'
def revFunc(curr):
    if curr.next_node is None:
        lst.head = curr
        return None

    revFunc(curr.next_node)
    curr.next_node.next_node = curr
    curr.next_node = None

revFunc(lst.head)

print lst               
# Head --> 500 --> 100 --> 30 --> 25 --> 20 --> 15 --> 10 --> 2 --> *