Given two numbers represented by two lists, write a function that returns the sum list. The sum list is a list representation of the addition of two input numbers.
// Java program to add two numbers
// represented by linked list
class LinkedList
{
static Node head1, head2;
static class Node
{
int data;
Node next;
Node(int d)
{
data = d;
next = null;
}
}
/* Adds contents of two linked
lists and return the head node
of resultant list */
Node addTwoLists(Node first,
Node second)
{
// res is head node of the
// resultant list
Node res = null;
Node prev = null;
Node temp = null;
int carry = 0, sum;
// while both lists exist
while (first != null ||
second != null)
{
// Calculate value of next digit
// in resultant list. The next
// digit is sum of following things
// (i) Carry
// (ii) Next digit of first
// list (if there is a next digit)
// (ii) Next digit of second
// list (if there is a next digit)
sum = carry + (first != null ? first.data : 0) +
(second != null ? second.data : 0);
// Update carry for next calculation
carry = (sum >= 10) ? 1 : 0;
// Update sum if it is greater
// than 10
sum = sum % 10;
// Create a new node with sum as data
temp = new Node(sum);
// if this is the first node then set
// it as head of the resultant list
if (res == null)
{
res = temp;
}
// If this is not the first
// node then connect it to the rest.
else
{
prev.next = temp;
}
// Set prev for next insertion
prev = temp;
// Move first and second pointers
// to next nodes
if (first != null)
{
first = first.next;
}
if (second != null)
{
second = second.next;
}
}
if (carry > 0)
{
temp.next = new Node(carry);
}
// return head of the resultant
// list
return res;
}
/* Utility function to print a
linked list */
void printList(Node head)
{
while (head != null)
{
System.out.print(head.data +
" ");
head = head.next;
}
System.out.println("");
}
// Driver Code
public static void main(String[] args)
{
LinkedList list = new LinkedList();
// Creating first list
list.head1 = new Node(7);
list.head1.next = new Node(5);
list.head1.next.next = new Node(9);
list.head1.next.next.next =
new Node(4);
list.head1.next.next.next.next =
new Node(6);
System.out.print("First List is ");
list.printList(head1);
// Creating second list
list.head2 = new Node(8);
list.head2.next = new Node(4);
System.out.print("Second List is ");
list.printList(head2);
// Add the two lists and see the result
Node rs = list.addTwoLists(head1, head2);
System.out.print("Resultant List is ");
list.printList(rs);
}
}
// This code is contributed by Mayank Jaiswal
Output:
First List is 7 5 9 4 6 Second List is 8 4 Resultant list is 5 0 0 5 6