[LeetCode][JavaScript]Copy List with Random Pointer

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.

https://leetcode.com/problems/copy-list-with-random-pointer/

第一把直接暴力两轮遍历。第一轮遍历copy链表，用hash表记录下各个节点，第二乱遍历去赋值链表里的random对象。

然后稍稍改进了一下，一次遍历里把能的找到的random都赋上，如果还没new出来，记到missed数组中，最后把missed的节点中的random再赋上值。

旧版:

 1 var copyRandomList = function(head) {
 2     var dict = {};
 3     var originNode = head;
 4     var newNode = new RandomListNode(0);
 5     var originHead = head;
 6     var newHead = newNode;
 7     while(originNode !== null){
 8         var temp = new RandomListNode(originNode.label);
 9            dict[originNode.label] = temp;
10            newNode.next = temp;
11
12         newNode = newNode.next;
13         originNode = originNode.next;
14     }
15
16     originNode = originHead;
17     newNode = newHead.next;
18     while(originNode !== null){
19         if(originNode.random !== null){
20             newNode.random = dict[originNode.random.label];
21         }
22         newNode = newNode.next;
23         originNode = originNode.next;
24     }
25     return newHead.next;
26 };

新版:

 1 /**
 2  * Definition for singly-linked list with a random pointer.
 3  * function RandomListNode(label) {
 4  *     this.label = label;
 5  *     this.next = this.random = null;
 6  * }
 7  */
 8
 9 /**
10  * @param {RandomListNode} head
11  * @return {RandomListNode}
12  */
13 var copyRandomList = function(head) {
14     var dict = {};
15     var missed = [];
16     var originNode = head;
17     var newNode = new RandomListNode(0);
18     var originHead = head;
19     var newHead = newNode;
20     while(originNode !== null){
21         var temp = new RandomListNode(originNode.label);
22            dict[originNode.label] = temp;
23            newNode.next = temp;
24            newNode = newNode.next;
25
26            if(originNode.random !== null){
27                if(dict[originNode.random.label]){
28                    newNode.random = dict[originNode.random.label];
29                }else{
30                    newNode.random = originNode.random.label;
31                    missed.push(newNode.label);
32                }
33         }
34         originNode = originNode.next;
35     }
36     for(var i = 0; i < missed.length; i++){
37         var curr = dict[missed[i]];
38         curr.random = dict[curr.random];
39     }
40     return newHead.next;
41 };