Function addTwoNumbers

add_two_numbers_2/solution.go:8–48

(l1 *structures.ListNode, l2 *structures.ListNode)

)

func addTwoNumbers(l1 *structures.ListNode, l2 *structures.ListNode) *structures.ListNode {
	num1 := depthFirstNum(l1)
	num2 := depthFirstNum(l2)

	var sum big.Int
	sum.Add(num1, num2)

	// single digit sum
	if len(sum.String()) == 1 {
		return &structures.ListNode{
			Val:  int(sum.Int64()),
			Next: nil,
		}
	}

	var sumList *structures.ListNode
	var current *structures.ListNode

	for sum.String() != "0" {
		var lastDigit big.Int
		lastDigit.Mod(&sum, big.NewInt(10))

		node := &structures.ListNode{
			Val:  int(lastDigit.Int64()),
			Next: nil,
		}
		if sumList == nil {
			sumList = node
		}
		if current == nil {
			current = node
		} else {
			current.Next = node
			current = current.Next
		}

		sum.Div(&sum, big.NewInt(10))
	}

	return sumList
}

func depthFirstNum(l *structures.ListNode) *big.Int {
	if l == nil {