[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/

 

 

 

 

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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:

var copyRandomList = function(head) {
    var dict = {};
    var originNode = head;
    var newNode = new RandomListNode(0);
    var originHead = head;
    var newHead = newNode;
    while(originNode !== null){
        var temp = new RandomListNode(originNode.label);
           dict[originNode.label] = temp;
           newNode.next = temp;

        newNode = newNode.next;
        originNode = originNode.next;
    }

    originNode = originHead;
    newNode = newHead.next;
    while(originNode !== null){
        if(originNode.random !== null){
            newNode.random = dict[originNode.random.label];
        }
        newNode = newNode.next;
        originNode = originNode.next;
    }
    return newHead.next;    
};

新版:

/**
 * Definition for singly-linked list with a random pointer.
 * function RandomListNode(label) {
 *     this.label = label;
 *     this.next = this.random = null;
 * }
 */

/**
 * @param {RandomListNode} head
 * @return {RandomListNode}
 */
var copyRandomList = function(head) {
    var dict = {};
    var missed = [];
    var originNode = head;
    var newNode = new RandomListNode(0);
    var originHead = head;
    var newHead = newNode;
    while(originNode !== null){
        var temp = new RandomListNode(originNode.label);
           dict[originNode.label] = temp;
           newNode.next = temp;
           newNode = newNode.next;

           if(originNode.random !== null){
               if(dict[originNode.random.label]){
                   newNode.random = dict[originNode.random.label];
               }else{
                   newNode.random = originNode.random.label;
                   missed.push(newNode.label);
               }
        }
        originNode = originNode.next;
    }
    for(var i = 0; i < missed.length; i++){
        var curr = dict[missed[i]];
        curr.random = dict[curr.random];
    }
    return newHead.next;    
};