C++ Program To Multiply Two Numbers Represented By Linked Lists
Last Updated :
15 Jun, 2022
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
Solution:
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:
C++
#include<bits/stdc++.h>
#include<stdio.h>
using namespace std;
struct Node
{
int data;
struct Node* next;
};
struct Node *newNode( int data)
{
struct Node *new_node =
( struct Node *) malloc ( sizeof ( struct Node));
new_node->data = data;
new_node->next = NULL;
return new_node;
}
void push( struct Node** head_ref,
int new_data)
{
struct Node* new_node =
newNode(new_data);
new_node->next = (*head_ref);
(*head_ref) = new_node;
}
long long multiplyTwoLists (Node* first,
Node* second)
{
long long N= 1000000007;
long long num1 = 0, num2 = 0;
while (first || second)
{
if (first)
{
num1 = (((num1) * 10) % N +
first -> data);
first = first -> next;
}
if (second)
{
num2 = (((num2) * 10) % N +
second -> data);
second = second->next;
}
}
return (((num1 % N) *
(num2 % N)) % N);
}
void printList( struct Node *node)
{
while (node != NULL)
{
cout << node -> data;
if (node -> next)
cout << "->" ;
node = node -> next;
}
cout << "" ;
}
int main()
{
struct Node* first = NULL;
struct Node* second = NULL;
push(&first, 6);
push(&first, 4);
push(&first, 9);
printf ( "First List is: " );
printList(first);
push(&second, 4);
push(&second, 8);
printf ( "Second List is: " );
printList(second);
cout << "Result is: " ;
cout << multiplyTwoLists(first,
second);
return 0;
}
|
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!
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