/// <summary>
/// 解法2，三步法
/// 基本思路：
/// 1. 复制链表每个节点，如：复制节点A得到A1，并将A1插入节点A后面
/// 2. 重新遍历链表，为每个复制的节点设置random，如A1.random = A.random.next;
/// 3、将链表拆分成原链表和复制后的链表
/// 第2步是第1步将复制节点插入到原节点后面的原因，这样复制节点的random就是原节点random的下一个节点
/// 可以查看docs/RandomListNode_solution2.png三步法的图示
/// </summary>
public RandomListNode Clone2(RandomListNode pHead)
{
if (pHead == null)
{
return(null);
}
RandomListNode cur = pHead;
while (cur != null)
{
RandomListNode next = new RandomListNode(cur.label);
next.next = cur.next;
cur.next = next;
cur = next.next;
}
cur = pHead;
while (cur != null)
{
if (cur.random != null)
{
cur.next.random = cur.random.next;
}
cur = cur.next.next;
}
cur = pHead;
RandomListNode head = pHead.next, temp;
while (cur != null && cur.next != null)
{
temp = cur.next;
cur.next = temp.next;
cur = temp;
}
return(head);
}
public void Test()
{
RandomListNode pHead = new RandomListNode(1);
pHead.next = new RandomListNode(2);
pHead.next.next = new RandomListNode(3);
pHead.next.next.next = new RandomListNode(4);
pHead.random = pHead.next.next;
pHead.next.random = pHead.next.next.next;
// Print(Clone(pHead));
Print(Clone2(pHead));
}
public void Print(RandomListNode pHead)
{
if (pHead == null)
{
Console.WriteLine("null");
return;
}
while (pHead != null)
{
Console.WriteLine(pHead.label + " " + pHead.random?.label);
pHead = pHead.next;
}
}
public RandomListNode Clone(RandomListNode pHead)
{
if (pHead == null)
{
return(null);
}
if (dic.ContainsKey(pHead))
{
return(dic[pHead]);
}
RandomListNode head = new RandomListNode(pHead.label);
dic[pHead] = head;
head.next = Clone(pHead.next);
head.random = Clone(pHead.random);
return(head);
}
