package q129

type TreeNode struct {
	Val   int
	Left  *TreeNode
	Right *TreeNode
}

func sumNums(node *TreeNode, prefix int) int {
	prefix = prefix*10 + node.Val

	if node.Left == nil && node.Right == nil {
		return prefix
	}

	sum := 0
	if node.Left != nil {
		sum += sumNums(node.Left, prefix)
	}
	if node.Right != nil {
		sum += sumNums(node.Right, prefix)
	}
	return sum
}

func sumNumbers(root *TreeNode) int {
	if root == nil {
		return 0
	}
	return sumNums(root, 0)
}

var _ = sumNumbers