138. Copy List with Random Pointer

A linked list is given such that each node contains an additional random pointer which could point to any node in the list or null.

Return a deep copy of the list.

code

注意某个节点没有next，但是有random的情况

/** * Definition for singly-linked list with a random pointer. * public class RandomListNode { *     public int label; *     public RandomListNode next, random; *     public RandomListNode(int x) { this.label = x; } * }; */public class Solution {    public RandomListNode CopyRandomList(RandomListNode head) {        if(head==null) return head;        RandomListNode clonehead = new RandomListNode(head.label);        if(head.next!=null)            clonehead.next = new RandomListNode(head.next.label);        if(head.random!=null)            clonehead.random = new RandomListNode(head.random.label);               RandomListNode next = CopyRandomList(head.next);        var cur = clonehead.next;        if(next!=null){            cur.next = next.next;            cur.random = next.random;        }            return clonehead;    }}