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。

1. 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。
2. 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：

1. 1. 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)

   2. 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

   3. 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。

   4. 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;
          }

   5. 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;
          }

   6. 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;
          }

   7. 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);
          }

   8. 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 
                      }
                  }                            
              }

   9. 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)+"
      
      ";
              }
              if(tempVegeMes.length>3){
                  resultMessage += tempVegeMes.slice(0,-1)+"
      
      ";
              }
              if(tempMeatMes.length>3){
                  resultMessage += tempMeatMes.slice(0,-1)+"
      
      ";
              }
              if(tempSoupMes.length>2){
                  resultMessage += tempSoupMes.slice(0,-1)+"
      
      ";
              }
              if(tempRiceMes.length>3){
                  resultMessage += tempRiceMes.slice(0,-1)+"
      
      ";
              }else if(eatRiceFlag){
                  resultMessage += "主食:"+tempPeoples+"碗米饭("+eachRicePayed+"元/碗)"+"
      
      ";
              }
              resultMessage += "共花费"+hasPayedMoney+"元"+"
      ";
      
              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：