package top100liked

// https://leetcode.cn/problems/copy-list-with-random-pointer/?envType=study-plan-v2&envId=top-100-liked

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

func copyRandomList(head *Node) *Node {
	if head == nil {
		return nil
	}

	m := make(map[*Node]*Node)
	cur := head

	var first *Node

	// 新旧节点映射
	for cur != nil {
		newNode := &Node{
			Val:    cur.Val,
			Next:   nil,
			Random: nil,
		}
		if first == nil {
			first = newNode
		}
		m[cur] = newNode
		cur = cur.Next
	}

	cur = head
	for cur != nil {
		if cur.Next != nil {
			m[cur].Next = m[cur.Next]
		}
		if cur.Random != nil {
			m[cur].Random = m[cur.Random]
		}
		cur = cur.Next
	}

	return first
}