package q117

type Node struct {
	Val   int
	Left  *Node
	Right *Node
	Next  *Node
}

func walk(node *Node, depth int, depths *[]*Node) {
	if node == nil {
		return
	}

	if depth > len(*depths) {
		*depths = append(*depths, nil)
	}
	if (*depths)[depth-1] != nil {
		(*depths)[depth-1].Next = node
	}
	(*depths)[depth-1] = node

	walk(node.Left, depth+1, depths)
	walk(node.Right, depth+1, depths)
}

func connect(root *Node) *Node {
	depths := []*Node{}
	walk(root, 1, &depths)

	return root
}

var _ = connect