AI Features
Home
Courses
Data Structures and Algorithms in Python

Solution Review: Sum Two Linked Lists

This lesson contains the solution review for the challenge of summing two linked lists.

We'll cover the following...

In this lesson, we investigate how to sum two singly linked lists. Check out the code below, after which, we will do a line by line analysis of it.

Implementation

def sum_two_lists(self, llist):
  p = self.head  
  q = llist.head
  sum_llist = LinkedList()
  carry = 0
  while p or q:
      if not p:
          i = 0
      else:
          i = p.data
      if not q:
          j = 0 
      else:
          j = q.data
      s = i + j + carry
      if s >= 10:
          carry = 1
          remainder = s % 10
          sum_llist.append(remainder)
      else:
          carry = 0
          sum_llist.append(s)
      if p:
          p = p.next
      if q:
          q = q.next
  return sum_llist
...