万事不求人系列之-智能点餐算法实现-JavaScript实现智能点餐

作为一个成长中的架构师，编码能力是万不能停止的，这个算法是之前在上一家单位帮助同事们自助订餐写的，纯爱好自己码敲的，刚好这段时间重新整理代码，发现了它，分享给大家，请大家品评指教。

使用场景介绍：随着各种订餐APP的出现，找饭馆团购券，为自己订点好吃的或者团购固定人数的券都很方便，但是很多时候我们遇到的是这样的场景：知道用餐人数是几人，但是总经费或人均消费标准有限制，让你点菜，你就得一方面考虑荤素搭配，有菜有汤有主食，另一方面还得考虑经费限制；还有一种情况是就这么多总经费，人数又不确定（如之前答应去临走又有事告假的），人少可以多点几个硬菜，人多只能综合考虑，拿主食顶上。这两种场景，对点菜的人提出了很高的要求，本算法就是针对此种情况，只要给出用餐人数或固定金额，自动为你科学点菜，妈妈再也不用担心你是个点菜盲。

基本效果截图：



如上图所示，输入人数点击开始点菜，系统自动会为你按照人均20的标准给出合理的菜单，这个人均标准是系统默认设置的，可以调整参数。如果输入人数的同时输入限定金额，则会以此金额为总花费的参考，保证不超过此金额下最优的给出建议菜单。当然如果同时输入了人数和限定金额，那么限定金额/人数不能低于系统设置的人均最低值，比如人数6人，限定金额50，人均很不到10块，下个毛管子。
3.基本原理：根据人数或限定金额得到本次菜单的可用总金额，同时根据人数按照一定荤素比例计算各类菜需要的个数，如6个人需要三个肉菜，一个蔬菜，一个凉菜，6分主食。（这个菜个数的计算是随机的，凉菜随机出现，主食可以是米饭也可以是饺子之类的，这个也是随机的。同时蔬菜和肉菜的比例虽然固定，但是每次随机会有小的调整，有上下浮动。）；得到每类菜的个数后开始从对应类别中随机选择，得到结果后按照金额的限制先排序再进行适当剔除或重选，使得总限定金额最优化，最后得到菜单并输出。
4.核心JS函数解释说明：

初始化默认参数：

var dishRate=[0.4,0.5,0.1]; // meat,vege,cold
var leastAveragePayed = 10; // Average consumption money
var defaultAveragePayed = 20; // default consumption money
var eatRiceFlag = true; // if eat rice or other things
var eatRiceRate = 8; // the rate people eat rice;
var eachRicePayed = 3; // each rice cost how much
var moneyLimit = false;
var outRangeMoney = 5; // can over money
9     var allDishArray = []; // 饭店所有的菜品

基本参数有:荤蔬搭配比例、人均最少消费、默认人均消费、要米饭还是其他主食、要米饭的概率、每碗米饭的价钱、是否有总消费限制、上下浮动的空间、饭店所有的菜品(这个需要初始化，将菜品按荤蔬凉菜汤米饭等类别分开，具体代码没有贴上来，看附件里)

点击“开始点菜"执行的方式解释：

function execute(){
var peoples=eatPeoples.value;
var money=payMoney.value;
if("" == peoples){
resultMes.innerText = "请输入用餐人数!";
return;
}
if(!/^\d+$/.test(peoples) || (("" != money) && !/^\d+$/.test(money))){
resultMes.innerText = "输入格式不对,请重新输入!";
return;
}
if(""!=money.replace(/[\s]+/g,"")){
moneyLimit = true;
}
        randomChooseDish(peoples,money);
}

做了一些基本的输入有效性验证，比如人数不能为空，输入格式校验等，然后进入randomChooseDish方法开始点菜

randomChooseDish方法如下：

function randomChooseDish(peoples,money){
var tempPeoples=parseInt(peoples);
var tempSumMoney= (""==money)?tempPeoples*parseInt(defaultAveragePayed):parseInt(money);
if(!checkCondition(tempPeoples,tempSumMoney)){
return;
}
var dishNumArray= getDishNumArray(tempPeoples);  //get dishNumArray

var hasPayedMoney=0;
if(eatRiceFlag){
// eat rice,reduce the rice money
hasPayedMoney = eachRicePayed*tempPeoples;
}

var beenChoosedArray = beginChooseDishesAndIndexs(dishNumArray);

sortChoosedArray(beenChoosedArray);
// when dishes are been choosed ,should check
checkAndChangeDishes(beenChoosedArray,hasPayedMoney,tempSumMoney);

// show result
showChooseResult(beenChoosedArray,hasPayedMoney,tempPeoples);
}

确定人数和总金额，checkCondition做基本的条件判断，比如人数不能少于2人，总金额/人数不能低于人均最低值等；getDishNumArray用于根据人数和初始化荤素比例计算每类菜品需要点的数量；beginChooseDishesAndIndexs用于开始随机点菜；sortChoosedArray用于排序，从贵到便宜，这样对于便宜的菜可以有更多搭配的方式；checkAndChangeDishes用于对选择的菜进行金额限制检查，如果超过限制则开始从最便宜的菜调整菜，直到菜单合格；showChooseResult用于将结果显示到页面上。下面是具体每个函数的源码，有注释。

checkCondition做基本的条件判断

function checkCondition(tempPeoples,tempSumMoney){
if(tempPeoples<2){
//alert();
resultMes.innerText = "一个人下馆子?太奢侈了.";
return false;
}
if(tempPeoples>25){
//alert();
resultMes.innerText = "人数太多,一桌坐不下!";
return false;
}

if(tempSumMoney<tempPeoples*leastAveragePayed){
//alert();
resultMes.innerText ="太抠了吧,都不到人均消费10块!";
return false;
}
return true;
}

getDishNumArray用于根据人数和初始化荤素比例计算每类菜品需要点的数量

// get meat,vege,cold numArray
function getDishNumArray(tempPeoples){
var numArray=[Math.ceil(tempPeoples*dishRate[0]),getRandomRate(8)?Math.ceil(tempPeoples*dishRate[1]):Math.floor(tempPeoples*dishRate[1]),Math.round(tempPeoples*dishRate[2])]; // meat,vege,cold

if(getSumArray(numArray)<=tempPeoples+1 || tempPeoples>=10){
var soupNum = Math.floor(tempPeoples/4)
numArray[numArray.length]=soupNum>2?2:soupNum; // add soup,soup num small then 2
}

eatRiceFlag = getRandomRate(eatRiceRate);
if(!eatRiceFlag){
// eat others
var mainRiceNum = Math.floor(tempPeoples/3);
numArray[numArray.length]=mainRiceNum>5?5:mainRiceNum; // add rice, mainrice nums small then 5
}
return numArray;
}

beginChooseDishesAndIndexs用于开始随机点菜

function beginChooseDishesAndIndexs(dishNumArray){
var resultArray=[];
var hasChoosedDishes=[]; // save be choosed dish
var hasChoosedIndexs=[]; // save be choosed in sourceArray index
var m = getRandom(dishNumArray.length); //random pos start
var dishLength=dishNumArray.length;
for(var i=0;i<dishLength;i++){
var index = ((i+m)>=dishLength)?i+m-dishLength:(i+m);
var dishNum=dishNumArray[index];
var tempSingleChoosed = []; // temp singleType choosed array
for(var n=0;n<dishNum;n++){
var singleTypeArray = allDishArray[index];
var singleTypeIndex = getRandom(singleTypeArray.length);
//alert(tempSingleChoosed+"and"+singleTypeIndex);
while(tempSingleChoosed.length <= singleTypeArray.length && checkIfInArray(tempSingleChoosed,singleTypeIndex)){
singleTypeIndex = getRandom(singleTypeArray.length);  // if now index is choosed，choose again
//alert("reGet"+singleTypeIndex);
}
if(tempSingleChoosed.length == singleTypeArray.length){
continue; // if singleTypeDish all been choosed, beak this circle,to next type dish
}
hasChoosedDishes[hasChoosedDishes.length] = singleTypeArray[singleTypeIndex]
tempSingleChoosed[tempSingleChoosed.length] = singleTypeIndex; // ramark the temp position
hasChoosedIndexs[hasChoosedIndexs.length] = index+","+singleTypeIndex; // ramark the position
}
} // all dish has choosed
resultArray.push(hasChoosedDishes);
resultArray.push(hasChoosedIndexs);
return resultArray;
}

sortChoosedArray用于排序

// when dishes been choosed ,sort it,from big to small
function sortChoosedArray(beenChoosedArray){
var hasChoosedDishes=beenChoosedArray[0]; // save be choosed dish
var hasChoosedIndexs=beenChoosedArray[1]; // save be choosed in sourceArray index
for(var i=0;i<hasChoosedDishes.length;i++){
for(var j=i;j<hasChoosedDishes.length;j++){
if(getDishAmount(hasChoosedDishes[i])>getDishAmount(hasChoosedDishes[j])){
var temp = hasChoosedDishes[i];
hasChoosedDishes[i] = hasChoosedDishes[j];
hasChoosedDishes[j] = temp;
// also should syn the choosedIndex
var temp2 = hasChoosedIndexs[i];
hasChoosedIndexs[i] = hasChoosedIndexs[j];
hasChoosedIndexs[j] = temp2;
}
}
}
//alert(hasChoosedDishes);
}

checkAndChangeDishes用于对选择的菜进行金额限制检查

// check if over money ,change less cost dish
function checkAndChangeDishes(beenChoosedArray,hasPayedMoney,tempSumMoney){
var outRange = moneyLimit?0:outRangeMoney;
while((hasPayedMoney+getSumArray(beenChoosedArray[0]))>tempSumMoney+outRange){
if(getRandomRate(8)){
changeOneToLessExpensive(beenChoosedArray);// random choose one dish then change it to less expensive
sortChoosedArray(beenChoosedArray); // reSort
}else{
removeDish(beenChoosedArray); // remove the most or least Expensive dish
}
}
}

showChooseResult用于将结果显示到页面上

// show the choose result
function showChooseResult(beenChoosedArray,hasPayedMoney,tempPeoples){
var hasChoosedDishes=beenChoosedArray[0]; // save be choosed dish
var hasChoosedIndexs=beenChoosedArray[1]; // save be choosed in sourceArray index
var tempcoldMes="凉菜:",tempVegeMes="蔬菜:",tempMeatMes="肉菜:",tempSoupMes="汤:",tempRiceMes="主食:";
for(var i in hasChoosedDishes){
var choosedIndex = hasChoosedIndexs[i];
var thisChoosedDish = hasChoosedDishes[i];
var thisDishArray = thisChoosedDish.split("@");
var allDishArrayIndex = (choosedIndex.split(","))[0];
switch (allDishArrayIndex){
case "0":tempMeatMes += thisDishArray[0]+":"+thisDishArray[1]+",";break;
case "1":tempVegeMes += thisDishArray[0]+":"+thisDishArray[1]+",";break;
case "2":tempcoldMes += thisDishArray[0]+":"+thisDishArray[1]+",";break;
case "3":tempSoupMes += thisDishArray[0]+":"+thisDishArray[1]+",";break;
case "4":tempRiceMes += thisDishArray[0]+":"+thisDishArray[1]+",";break;
default:break;
}
hasPayedMoney += parseInt(thisDishArray[1]);
}
var resultMessage="";
if(tempcoldMes.length>3){
resultMessage += tempcoldMes.slice(0,-1)+"\n\n";
}
if(tempVegeMes.length>3){
resultMessage += tempVegeMes.slice(0,-1)+"\n\n";
}
if(tempMeatMes.length>3){
resultMessage += tempMeatMes.slice(0,-1)+"\n\n";
}
if(tempSoupMes.length>2){
resultMessage += tempSoupMes.slice(0,-1)+"\n\n";
}
if(tempRiceMes.length>3){
resultMessage += tempRiceMes.slice(0,-1)+"\n\n";
}else if(eatRiceFlag){
resultMessage += "主食:"+tempPeoples+"碗米饭("+eachRicePayed+"元/碗)"+"\n\n";
}
resultMessage += "共花费"+hasPayedMoney+"元"+"\n";

resultMes.innerText = resultMessage;
}

　　　　　　其他都是一些辅助性的函数，见附件。

5.附件点击下载：