package q138

type Node struct {
	Val    int
	Next   *Node
	Random *Node
}

func copyRandomList(head *Node) *Node {
	idx := make(map[*Node]*Node, 256)

	p := head
	for p != nil {
		newNode := *p // copy
		idx[p] = &newNode
		p = p.Next
	}

	p = head
	for p != nil {
		newNode := idx[p]
		if newNode.Next != nil {
			newNode.Next = idx[newNode.Next]
		}
		if newNode.Random != nil {
			newNode.Random = idx[newNode.Random]
		}
		p = p.Next
	}

	return idx[head]
}

var _ = copyRandomList