题解复杂链表的深拷贝

两种解决方案；
第一种：

/*
*解题思路：
*1、遍历链表，复制每个结点，如复制结点A得到A1，将结点A1插到结点A后面；
*2、重新遍历链表，复制老结点的随机指针给新结点，如A1.random = A.random.next;
*3、拆分链表，将链表拆分为原链表和复制后的链表
*/
public class Solution {
    public RandomListNode Clone(RandomListNode pHead) {
        if(pHead == null) {
            return null;
        }

        RandomListNode currentNode = pHead;
        //1、复制每个结点，如复制结点A得到A1，将结点A1插到结点A后面；
        while(currentNode != null){
            RandomListNode cloneNode = new RandomListNode(currentNode.label);
            RandomListNode nextNode = currentNode.next;
            currentNode.next = cloneNode;
            cloneNode.next = nextNode;
            currentNode = nextNode;
        }

        currentNode = pHead;
        //2、重新遍历链表，复制老结点的随机指针给新结点，如A1.random = A.random.next;
        while(currentNode != null) {
            currentNode.next.random = currentNode.random==null?null:currentNode.random.next;
            currentNode = currentNode.next.next;
        }

        //3、拆分链表，将链表拆分为原链表和复制后的链表
        currentNode = pHead;
        RandomListNode pCloneHead = pHead.next;
        while(currentNode != null) {
            RandomListNode cloneNode = currentNode.next;
            currentNode.next = cloneNode.next;
            cloneNode.next = cloneNode.next==null?null:cloneNode.next.next;
            currentNode = currentNode.next;
        }

        return pCloneHead;
    }
}

第二种：

class RandomListNode {
    int label;
    RandomListNode next = null;
    RandomListNode random = null;

    RandomListNode(int label) {
        this.label = label;
    }
}
import java.util.*;

public class Solution {
    HashMap<RandomListNode,RandomListNode>re=new HashMap<>();
    public RandomListNode Clone(RandomListNode pHead)
    {
        RandomListNode tempr=null;

        if(pHead==null){
            return tempr;
        }
        if(!re.isEmpty()&&re.containsKey(pHead)) {
            return re.get(pHead);
        }
        int val=pHead.label;
        tempr=new RandomListNode(val);
        re.put(pHead,tempr);
        tempr.next=Clone(pHead.next);
        re.get(pHead).next=tempr.next;
        tempr.random=Clone(pHead.random);
        re.get(pHead).next=tempr.next;
        re.get(pHead).random=tempr.random;
        return tempr;
    }0
}