Python Program To Multiply Two Numbers Represented By Linked Lists

Last Updated : 31 Jul, 2023

Given two numbers represented by linked lists, write a function that returns the multiplication of these two linked lists.

Examples:

Input: 9->4->6
        8->4
Output: 79464
Input: 3->2->1
        1->2
Output: 3852

Python Program To Multiply Two Numbers Represented By Linked Lists

Traverse both lists and generate the required numbers to be multiplied and then return the multiplied values of the two numbers.
Algorithm to generate the number from linked list representation:

1) Initialize a variable to zero
2) Start traversing the linked list
3) Add the value of the first node to this variable
4) From the second node, multiply the variable by 10
   and also take the modulus of this value by 10^9+7
   and then add the value of the node to this 
   variable.
5) Repeat step 4 until we reach the last node of the list.

Use the above algorithm with both linked lists to generate the numbers.

Below is the program for multiplying two numbers represented as linked lists:

Python3

# Python3 to multiply two numbers # represented as Linked Lists    # Linked list node class  class Node:             # Function to initialize the node       def __init__(self, data):                 self.data = data          self.next = None         # Linked List Class class LinkedList:        # Function to initialize the     # LinkedList class.     def __init__(self):            # Initialize head as None         self.head = None        # Function to insert a node at the     # beginning of the Linked List     def push(self, new_data):                 # Create a new Node          new_node = Node(new_data)             # Make next of the new Node          # as head          new_node.next = self.head             # Move the head to point to          # new Node          self.head = new_node                # Function to print the Linked      # List     def printList(self):                 ptr = self.head           while (ptr != None):             print(ptr.data,                    end = '')             if ptr.next != None:                 print('->',                        end = '')                             ptr = ptr.next                        print()    # Multiply contents of two Linked  # Lists def multiplyTwoLists(first, second):       num1 = 0     num2 = 0      first_ptr = first.head     second_ptr = second.head          while first_ptr != None or second_ptr != None:         if first_ptr != None:             num1 = (num1 * 10) + first_ptr.data             first_ptr = first_ptr.next              if second_ptr != None:             num2 = (num2 * 10) + second_ptr.data             second_ptr = second_ptr.next          return num1 * num2    # Driver code if __name__=='__main__':        first = LinkedList()     second = LinkedList()        # Create first Linked List 9->4->6     first.push(6)     first.push(4)     first.push(9)      # Printing first Linked List     print("First list is: ", end = '')     first.printList()        # Create second Linked List 8->4     second.push(4)     second.push(8)      # Printing second Linked List     print("Second List is: ",             end = '')     second.printList()        # Multiply two linked list and     # print the result     result = multiplyTwoLists(first,                                second)     print("Result is: ", result) # This code is contributed by kirtishsurangalikar

Output:

First List is: 9->4->6
Second List is: 8->4
Result is: 79464

Time Complexity: O(max(n1, n2)), where n1 and n2 represents the number of nodes present in the first and second linked list respectively.
Auxiliary Space: O(1), no extra space is required, so it is a constant.

Please refer complete article on Multiply two numbers represented by Linked Lists for more details!

Python Program For Adding 1 To A Number Represented As Linked List

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Python Program To Multiply Two Numbers Represented By Linked Lists

Python Program To Multiply Two Numbers Represented By Linked Lists

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