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：

巴特西

万事不求人系列之-智能点餐算法实现-JavaScript实现智能点餐

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