Problem Challenge 1

We'll cover the following

- - Reverse alternating K-element Sub-list (medium)
- - Try it yourself

Reverse alternating K-element Sub-list (medium) #

Given the head of a LinkedList and a number ‘k’, reverse every alternating ‘k’ sized sub-list starting from the head.

If, in the end, you are left with a sub-list with less than ‘k’ elements, reverse it too.

Try it yourself #

Try solving this question here:

Java

Python3

C++

from __future__ import print_function
 
 
class Node:
  def __init__(self, value, next=None):
    self.value = value
    self.next = next
 
  def print_list(self):
    temp = self
    while temp is not None:
      print(temp.value, end=" ")
      temp = temp.next
    print()
 
 
def reverse_alternate_k_elements(head, k):
  # TODO: Write your code here
  return head
 
 
def main():
  head = Node(1)
  head.next = Node(2)
  head.next.next = Node(3)
  head.next.next.next = Node(4)
  head.next.next.next.next = Node(5)
  head.next.next.next.next.next = Node(6)
  head.next.next.next.next.next.next = Node(7)
  head.next.next.next.next.next.next.next = Node(8)
 
  print("Nodes of original LinkedList are: ", end='')
  head.print_list()
  result = reverse_alternate_k_elements(head, 2)
  print("Nodes of reversed LinkedList are: ", end='')
  result.print_list()
 
 
main()
 

Output

0.724s

Nodes of original LinkedList are: 1 2 3 4 5 6 7 8 Nodes of reversed LinkedList are: 1 2 3 4 5 6 7 8

Mark as Completed

← Back

Reverse every K-element Sub-list (medium)

Solution Review: Problem Challenge 1