题目：

题解：

func copyRandomList(head *Node) *Node {if head == nil {return nil}for node := head; node != nil; node = node.Next.Next {node.Next = &Node{Val: node.Val, Next: node.Next}}for node := head; node != nil; node = node.Next.Next {if node.Random != nil {node.Next.Random = node.Random.Next}}headNew := head.Nextfor node := head; node != nil; node = node.Next {nodeNew := node.Nextnode.Next = node.Next.Nextif nodeNew.Next != nil {nodeNew.Next = nodeNew.Next.Next}}return headNew
}