public static ListNode SumListsForwardRepresentation(ListNode headA, ListNode headB)
{
int headALength = GetLength(headA);
int headBLength = GetLength(headB);
Carry carry = new Carry();
ListNode result = new ListNode();
if (headALength == headBLength)
{
result = SumListsForwardRepresentation(headA, headB, carry);
}
else
{
if (headALength > headBLength)
{
headB = AppendZerosInFront(headB, Math.Abs(headALength - headBLength));
}
else
{
headA = AppendZerosInFront(headA, Math.Abs(headALength - headBLength));
}
result = SumListsForwardRepresentation(headA, headB, carry);
}
if (carry.val > 0)
{
ListNode carryNode = new ListNode(carry.val);
carryNode.Next = result;
return(carryNode);
}
return(result);
}
private static ListNode SumListsForwardRepresentation(ListNode headA, ListNode headB, Carry carry)
{
if (headA == null || headB == null)
{
return(null);
}
ListNode next = SumListsForwardRepresentation(headA.Next, headB.Next, carry);
int value = carry.val + headA.Data + headB.Data;
ListNode result = new ListNode();
result.Data = value % 10;
carry.val = value >= 10 ? 1 : 0;
result.Next = next;
return(result);
}