万事不求人系列之-智能点餐算法实现-JavaScript实现智能点餐

浏览数：28 / 时间：2015年06月08日

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：

技术分享

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：

1     var dishRate=[0.4,0.5,0.1]; // meat,vege,cold
2     var leastAveragePayed = 10; // Average consumption money
3     var defaultAveragePayed = 20; // default consumption money    
4     var eatRiceFlag = true; // if eat rice or other things
5     var eatRiceRate = 8; // the rate people eat rice;
6     var eachRicePayed = 3; // each rice cost how much
7     var moneyLimit = false;    
8     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：

 1     function execute(){
 2         var peoples=eatPeoples.value;
 3         var money=payMoney.value;        
 4         if("" == peoples){            
 5             resultMes.innerText = "请输入用餐人数!";
 6             return;
 7         }
 8         if(!/^\d+$/.test(peoples) || (("" != money) && !/^\d+$/.test(money))){        
 9             resultMes.innerText = "输入格式不对,请重新输入!";
10             return;
11         }
12         if(""!=money.replace(/[\s]+/g,"")){
13             moneyLimit = true;
14         }
15         randomChooseDish(peoples,money);        
16     }

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：

 1     function randomChooseDish(peoples,money){
 2         var tempPeoples=parseInt(peoples);
 3         var tempSumMoney= (""==money)?tempPeoples*parseInt(defaultAveragePayed):parseInt(money);        
 4         if(!checkCondition(tempPeoples,tempSumMoney)){
 5             return;
 6         }
 7         var dishNumArray= getDishNumArray(tempPeoples);  //get dishNumArray    
 8         
 9         var hasPayedMoney=0;    
10         if(eatRiceFlag){
11             // eat rice,reduce the rice money
12             hasPayedMoney = eachRicePayed*tempPeoples;
13         }    
14 
15         var beenChoosedArray = beginChooseDishesAndIndexs(dishNumArray);
16         
17         sortChoosedArray(beenChoosedArray);
18         // when dishes are been choosed ,should check
19         checkAndChangeDishes(beenChoosedArray,hasPayedMoney,tempSumMoney);    
20         
21         // show result
22         showChooseResult(beenChoosedArray,hasPayedMoney,tempPeoples);        
23     }

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

 1     function checkCondition(tempPeoples,tempSumMoney){        
 2         if(tempPeoples<2){
 3             //alert();
 4             resultMes.innerText = "一个人下馆子?太奢侈了.";
 5             return false;
 6         }
 7         if(tempPeoples>25){
 8             //alert();
 9             resultMes.innerText = "人数太多,一桌坐不下!";
10             return false;
11         }
12 
13         if(tempSumMoney<tempPeoples*leastAveragePayed){
14             //alert();
15             resultMes.innerText ="太抠了吧,都不到人均消费10块!";
16             return false;
17         }
18         return true;
19     }

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

 1     // get meat,vege,cold numArray
 2     function getDishNumArray(tempPeoples){
 3         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    
 4         
 5         if(getSumArray(numArray)<=tempPeoples+1 || tempPeoples>=10){
 6             var soupNum = Math.floor(tempPeoples/4)
 7             numArray[numArray.length]=soupNum>2?2:soupNum; // add soup,soup num small then 2
 8         }
 9 
10         eatRiceFlag = getRandomRate(eatRiceRate);
11         if(!eatRiceFlag){
12             // eat others
13             var mainRiceNum = Math.floor(tempPeoples/3);
14             numArray[numArray.length]=mainRiceNum>5?5:mainRiceNum; // add rice, mainrice nums small then 5
15         }
16         return numArray;
17     }

beginChooseDishesAndIndexs用于开始随机点菜

 1     function beginChooseDishesAndIndexs(dishNumArray){
 2         var resultArray=[];
 3         var hasChoosedDishes=[]; // save be choosed dish
 4         var hasChoosedIndexs=[]; // save be choosed in sourceArray index
 5         var m = getRandom(dishNumArray.length); //random pos start
 6         var dishLength=dishNumArray.length;        
 7         for(var i=0;i<dishLength;i++){
 8             var index = ((i+m)>=dishLength)?i+m-dishLength:(i+m);
 9             var dishNum=dishNumArray[index];
10             var tempSingleChoosed = []; // temp singleType choosed array            
11             for(var n=0;n<dishNum;n++){
12                 var singleTypeArray = allDishArray[index];
13                 var singleTypeIndex = getRandom(singleTypeArray.length);    
14                 //alert(tempSingleChoosed+"and"+singleTypeIndex);
15                 while(tempSingleChoosed.length <= singleTypeArray.length && checkIfInArray(tempSingleChoosed,singleTypeIndex)){
16                     singleTypeIndex = getRandom(singleTypeArray.length);  // if now index is choosed，choose again        
17                     //alert("reGet"+singleTypeIndex);
18                 }
19                 if(tempSingleChoosed.length == singleTypeArray.length){
20                     continue; // if singleTypeDish all been choosed, beak this circle,to next type dish
21                 }
22                 hasChoosedDishes[hasChoosedDishes.length] = singleTypeArray[singleTypeIndex]
23                 tempSingleChoosed[tempSingleChoosed.length] = singleTypeIndex; // ramark the temp position
24                 hasChoosedIndexs[hasChoosedIndexs.length] = index+","+singleTypeIndex; // ramark the position
25             }
26         } // all dish has choosed 
27         resultArray.push(hasChoosedDishes);
28         resultArray.push(hasChoosedIndexs);        
29         return resultArray;
30     }

sortChoosedArray用于排序

 1     // when dishes been choosed ,sort it,from big to small
 2     function sortChoosedArray(beenChoosedArray){    
 3         var hasChoosedDishes=beenChoosedArray[0]; // save be choosed dish
 4         var hasChoosedIndexs=beenChoosedArray[1]; // save be choosed in sourceArray index        
 5         for(var i=0;i<hasChoosedDishes.length;i++){
 6             for(var j=i;j<hasChoosedDishes.length;j++){
 7                 if(getDishAmount(hasChoosedDishes[i])>getDishAmount(hasChoosedDishes[j])){
 8                     var temp = hasChoosedDishes[i];
 9                     hasChoosedDishes[i] = hasChoosedDishes[j];
10                     hasChoosedDishes[j] = temp;
11                     // also should syn the choosedIndex
12                     var temp2 = hasChoosedIndexs[i];
13                     hasChoosedIndexs[i] = hasChoosedIndexs[j];
14                     hasChoosedIndexs[j] = temp2;
15                 }
16             }
17         }
18         //alert(hasChoosedDishes);
19     }

checkAndChangeDishes用于对选择的菜进行金额限制检查

 1     // check if over money ,change less cost dish
 2     function checkAndChangeDishes(beenChoosedArray,hasPayedMoney,tempSumMoney){    
 3             var outRange = moneyLimit?0:outRangeMoney;
 4             while((hasPayedMoney+getSumArray(beenChoosedArray[0]))>tempSumMoney+outRange){                
 5                 if(getRandomRate(8)){
 6                     changeOneToLessExpensive(beenChoosedArray);// random choose one dish then change it to less expensive
 7                     sortChoosedArray(beenChoosedArray); // reSort
 8                 }else{
 9                     removeDish(beenChoosedArray); // remove the most or least Expensive dish 
10                 }
11             }                            
12         }

showChooseResult用于将结果显示到页面上

 1     // show the choose result
 2     function showChooseResult(beenChoosedArray,hasPayedMoney,tempPeoples){
 3         var hasChoosedDishes=beenChoosedArray[0]; // save be choosed dish
 4         var hasChoosedIndexs=beenChoosedArray[1]; // save be choosed in sourceArray index
 5         var tempcoldMes="凉菜:",tempVegeMes="蔬菜:",tempMeatMes="肉菜:",tempSoupMes="汤:",tempRiceMes="主食:";    
 6         for(var i in hasChoosedDishes){
 7             var choosedIndex = hasChoosedIndexs[i];
 8             var thisChoosedDish = hasChoosedDishes[i];
 9             var thisDishArray = thisChoosedDish.split("@");
10             var allDishArrayIndex = (choosedIndex.split(","))[0];
11             switch (allDishArrayIndex){
12                 case "0":tempMeatMes += thisDishArray[0]+":"+thisDishArray[1]+",";break;
13                 case "1":tempVegeMes += thisDishArray[0]+":"+thisDishArray[1]+",";break;
14                 case "2":tempcoldMes += thisDishArray[0]+":"+thisDishArray[1]+",";break;
15                 case "3":tempSoupMes += thisDishArray[0]+":"+thisDishArray[1]+",";break;
16                 case "4":tempRiceMes += thisDishArray[0]+":"+thisDishArray[1]+",";break;
17                 default:break;
18             }
19             hasPayedMoney += parseInt(thisDishArray[1]);
20         }
21         var resultMessage="";
22         if(tempcoldMes.length>3){
23             resultMessage += tempcoldMes.slice(0,-1)+"\n\n";
24         }
25         if(tempVegeMes.length>3){
26             resultMessage += tempVegeMes.slice(0,-1)+"\n\n";
27         }
28         if(tempMeatMes.length>3){
29             resultMessage += tempMeatMes.slice(0,-1)+"\n\n";
30         }
31         if(tempSoupMes.length>2){
32             resultMessage += tempSoupMes.slice(0,-1)+"\n\n";
33         }
34         if(tempRiceMes.length>3){
35             resultMessage += tempRiceMes.slice(0,-1)+"\n\n";
36         }else if(eatRiceFlag){
37             resultMessage += "主食:"+tempPeoples+"碗米饭("+eachRicePayed+"元/碗)"+"\n\n";
38         }
39         resultMessage += "共花费"+hasPayedMoney+"元"+"\n";
40 
41         resultMes.innerText = resultMessage;
42     }