Can someone help me with the below question:

there are two linked lists, I need sum of the given linked lists in single traversal without extra space.
and return result linkedlist.

Example:
head1 -> 3 -> 8 -> 4 -> null
head2 -> 7 -> 6 -> 2 -> 2 -> null

sum:
384
+7622
8006
result -> 8 -> 0 -> 0 -> 6