js实现prim+优先队列

最近在学算法，沉迷于js的我，就想用js敲一敲这个prim算法，至于prim算法具体是什么，怎么回事，大家可以自行搜索，这里只贴上代码和部分注解
数据是从文件里读出来的所以用了一下node.js，数据格式如下
7 9
1 2 28
1 6 10
2 7 14
2 3 16
6 5 25
7 5 24
7 4 18
3 4 12
5 4 22

var fs = require('fs')var path = require('path');var Q = require("q");var MAX = 100000;var dingdian;//顶点数var bian;//边数var edge = [];//矩阵var node = [] // 记录节点var addNew = []; //设置顶点是否加入到集合// 优先队列数据结构 function PriorityQueue() {    var items = [];    function QueueElement (element, priority){ // {1}        this.element = element;        this.priority = priority;    }    this.enqueue = function(element, priority){        var queueElement = new QueueElement(element, priority);        var added = false;        for (var i=0; i< items.length; i++){            if (queueElement.priority < items[i].priority){ // {2}                items.splice(i,0,queueElement);             // {3}                added = true;                break; // {4}            }        }        if (!added){            items.push(queueElement); //{5}        }    };    this.dequeue = function(){        return items.shift();    };    this.front = function(){        return items[0];    };    this.isEmpty = function(){        return items.length == 0;    };    this.size = function(){        return items.length;    }; }var  q = new PriorityQueue(); //创建优先队列//初始化输入矩阵function initRect(length) {    for(var i = 1; i<length+1; i++) {        edge[i] = [];        for(var j=1; j<length+1;j++) {            edge[i][j] = MAX;        }    }}//读取数据function preadFile (file){      var deferred = Q.defer();      fs.readFile(file,'utf-8', function(err,data){        if(!err){          deferred.resolve(data);        }else{          deferred.reject(err);        }      });        return deferred.promise;    }var filein = path.resolve('input.txt')preadFile(filein).then(function(data){    var arr = data.split(/\r\n/) //回车空行分割读取    // console.log(arr)   for(var i=0;i<arr.length;i++) {        var _arr = arr[i].split(' ');        if(_arr.length === 2) {            dingdian = parseInt(_arr[0]);            bian = parseInt(_arr[1])            initRect(dingdian);//进行初始化        }else if(_arr.length === 3) { //添加数据到矩阵            edge[_arr[0]][_arr[1]] = parseInt(_arr[2]);            edge[_arr[1]][_arr[0]] = parseInt(_arr[2]);        }else {            return;        }   }        //求值        var result = prim(dingdian, edge);        var _arr = [];        for(key in result) {            _arr[key] = result[key].priority        }        _arr.splice(0,1);        var max = Math.max.apply(Math, _arr)        console.log(max)//结果是25});// 开始prim算法 prim([顶点数],[矩阵])function prim(dingdian, edge) {    for(var i=1; i<dingdian+1; i++) {        node[i] = {}        node[i].element = i;        node[i].priority = MAX;        addNew[i] = false; //把所有点都设置成没有放入    }    // console.log('node',node[1])    node[1].priority = 0; //从起始点开始找    q.enqueue(node[1].element, node[1].priority)//把权最小的放入队列    while(!q.isEmpty()) {        var _q = q.front();        q.dequeue();        var flag = _q.element;//        if(addNew[flag]) {            continue;        }        addNew[flag] = true;        for(var j=1; j<dingdian+1; j++) {            if(j!=flag && !addNew[j] && node[j].priority > edge[flag][j]){                node[j].priority = edge[flag][j];                q.enqueue(node[j].element, node[j].priority)            }        }    }    return node}