# Java Program To Multiply Two Numbers Represented By Linked Lists

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 first node to this variable
4) From the second node, multiply the variable by 10
and also take 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 of linked lists to generate the numbers.

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

## Java

 `// Java program to Multiply two numbers``// represented as linked lists``import` `java.util.*;` `public` `class` `GFG{` `// Linked list node``static` `class` `Node``{``    ``int` `data;``    ``Node next;``        ` `    ``Node(``int` `data)``    ``{``        ``this``.data = data;``        ``next = ``null``;``    ``}``}` `// Multiply contents of two linked lists``static` `long` `multiplyTwoLists(Node first, ``                             ``Node second)``{``    ``long` `N = ``1000000007``;``    ``long` `num1 = ``0``, num2 = ``0``;` `    ``while` `(first != ``null` `|| ``           ``second !=  ``null``)``    ``{            ``        ``if``(first != ``null``)``        ``{``            ``num1 = (((num1) * ``10``) % N + ``                      ``first.data);``            ``first = first.next;``        ``}``            ` `        ``if``(second != ``null``)``        ``{``            ``num2 = (((num2) * ``10``) % N + ``                      ``second.data);``            ``second = second.next;``        ``}            ``    ``}``    ``return` `(((num1 % N) * ``             ``(num2 % N)) % N);``}` `// A utility function to print a ``// linked list``static` `void` `printList(Node node)``{``    ``while``(node != ``null``)``    ``{``        ``System.out.print(node.data);``        ``if``(node.next != ``null``)``            ``System.out.print(``"->"``);``        ``node = node.next;``    ``}``    ``System.out.println();``}` `// Driver code``public` `static` `void` `main(String args[])``{``    ``// Create first list 9->4->6``    ``Node first = ``new` `Node(``9``);``    ``first.next = ``new` `Node(``4``);``    ``first.next.next = ``new` `Node(``6``);``    ``System.out.print(``"First List is: "``);``    ``printList(first);` `    ``// Create second list 8->4``    ``Node second = ``new` `Node(``8``);``    ``second.next = ``new` `Node(``4``);``    ``System.out.print(``"Second List is: "``);``    ``printList(second);` `    ``// Multiply the two lists and see result``    ``System.out.print(``"Result is: "``);``    ``System.out.println(multiplyTwoLists(first, second));``}``}``// This code is contributed by adityapande88`

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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