/*
* 优先队列
* 出队时，先找出优先级最高的元素，再按照先进先出出队。
* */
function Queue(){
    this.dataStore = [];//存放队列的数组，初始化为空
    this.enqueue = enqueue;//向队列尾部添加一个元素
    this.dequeue = dequeue;//出队时，先找出优先级最高的元素，再按照先进先出出队。
    this.theFront = theFront;//读取队首的元素
    this.back = back;//对取队尾的元素
    this.toStrings = toStrings;//显示队列内的所有元素
    this.empty = empty;//判断队列是否为空
}
/*先定义存储队列元素的对象*/
function Patient(name,code){
    this.name = name;//code是一个整数，表示患者的优先级
    this.code = code;
}

function enqueue(element){
    this.dataStore.push(element);
}

function dequeue(){
    var minindex = 0;
    var priority = this.dataStore[0].code;
    for(var i = 1;i<this.dataStore.length;i++){
        if(this.dataStore[i].code < priority){
            priority = this.dataStore[i].code;
            minindex = i;
        }
    }
    return this.dataStore.splice(minindex,1);
}

function theFront(){
    return this.dataStore[0];
}

function back(){
    return this.dataStore[this.dataStore.length-1];
}

function toStrings(){
    return this.dataStore;
}

function empty(){
    if(this.dataStore.length == 0){
       return true;
    }else{
        return false;
    }
}

/*优先队列的实现*/
var ed = new Queue();
var p = new Patient("aa",5);
ed.enqueue(p);
var p = new Patient("bb",4);
ed.enqueue(p);
var p = new Patient("cc",3);
ed.enqueue(p);
var p = new Patient("dd",3);
ed.enqueue(p);
var p = new Patient("ee",1);
ed.enqueue(p);
console.log(ed.toStrings());
console.log(ed.dequeue());//[ Patient { name: ‘ee‘, code: 1 } ]
console.log(ed.dequeue());//[ Patient { name: ‘cc‘, code: 3 } ]
console.log(ed.dequeue());//[ Patient { name: ‘dd‘, code: 3 } ]