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：

1. 1. 初始化默认参数：

      1     var dishRate=[0.4,0.5,0.1]; // meat,vege,cold2     var leastAveragePayed = 10; // Average consumption money3     var defaultAveragePayed = 20; // default consumption money    4     var eatRiceFlag = true; // if eat rice or other things5     var eatRiceRate = 8; // the rate people eat rice;6     var eachRicePayed = 3; // each rice cost how much7     var moneyLimit = false;    8     var outRangeMoney = 5; // can over money9     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：

       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

   3. 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 money12             hasPayedMoney = eachRicePayed*tempPeoples;13         }    14 15         var beenChoosedArray = beginChooseDishesAndIndexs(dishNumArray);16         17         sortChoosedArray(beenChoosedArray);18         // when dishes are been choosed ,should check19         checkAndChangeDishes(beenChoosedArray,hasPayedMoney,tempSumMoney);    20         21         // show result22         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。

   4. 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     }

   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

       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 others13             var mainRiceNum = Math.floor(tempPeoples/3);14             numArray[numArray.length]=mainRiceNum>5?5:mainRiceNum; // add rice, mainrice nums small then 515         }16         return numArray;17     }

   6. 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 dish21                 }22                 hasChoosedDishes[hasChoosedDishes.length] = singleTypeArray[singleTypeIndex]23                 tempSingleChoosed[tempSingleChoosed.length] = singleTypeIndex; // ramark the temp position24                 hasChoosedIndexs[hasChoosedIndexs.length] = index+","+singleTypeIndex; // ramark the position25             }26         } // all dish has choosed 27         resultArray.push(hasChoosedDishes);28         resultArray.push(hasChoosedIndexs);        29         return resultArray;30     }

   7. 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 choosedIndex12                     var temp2 = hasChoosedIndexs[i];13                     hasChoosedIndexs[i] = hasChoosedIndexs[j];14