FreeCodeCamp---advanced Algorithm Scripting解法

Exact Change

设计一个收银程序 checkCashRegister() ，其把购买价格(price)作为第一个参数 , 付款金额 (cash)作为第二个参数, 和收银机中零钱 (cid) 作为第三个参数.

cid 是一个二维数组，存着当前可用的找零.

当收银机中的钱不够找零时返回字符串 "Insufficient Funds". 如果正好则返回字符串 "Closed".

否则, 返回应找回的零钱列表,且由大到小存在二维数组中.

function checkCashRegister(price, cash, cid) {
  var arr=[];  //应找回的零钱列表
  var cashPrice=[];  //一种钱代表的金额
  var cashName=[];  //钱的名字
  var cashItemSum=[];  //一种钱的总数
  var change=Math.round((cash-price)*100)/100;   //要找回的零钱
  var sumCash=0;
  cid.forEach(function(item,index,array){
    if(item[1]>0){
      cashName.push(item[0]);
      cashItemSum.push(item[1]);
      sumCash += item[1];
    }
  });
  
  cashPrice=cashName.map(function(item,index,array){
    switch (item){
      case "PENNY":
        return 0.01;
      case "NICKEL":
        return 0.05;
      case "DIME":
        return 0.1;
      case "QUARTER":
        return 0.25;
      case "ONE":
        return 1;
      case "FIVE":
        return 5;
      case "TEN":
        return 10;
      case "TWENTY":
        return 20;
      case "ONE HUNDRED":
        return 100;
    }
  });
  
  
  sumCash=Math.round(sumCash*100)/100; //对sumCash保留两位小数
    
  switch (true){
    case change>sumCash:
      return "Insufficient Funds";
    case change === sumCash:
      return "Closed";
    default:
      approachChange(change);
      if(arr.length===0){
        return "Insufficient Funds";
      }else{
        return arr;
      }
  }
  
  
  
  function approachChange(change){
    var index=0;
    if(change>cashPrice[cashPrice.length-1]){
      index=cashPrice.length-1;
    }
    
    for(var i=0; i<cashPrice.length-1; i++){
      if(cashPrice[i]<=change && change<cashPrice[i+1] && cashItemSum[i]!==0){
         index=i;
      }
    }
   
    var itemNeedSum=Math.floor(change/cashPrice[index]) * cashPrice[index];
    var needMin=Math.min(itemNeedSum,cashItemSum[index]);
    var x=Math.round( (change-needMin)*100 )/100;
    
    if(x>0 && index===0){
      return;
    }
    
    arr.push([cashName[index], needMin]);      
    
    
    if(x===0){
      return;
    }else{
      cashPrice=cashPrice.slice(0,index);
      approachChange(x);
    }  
  }
  
}


checkCashRegister(19.50, 20.00, [["PENNY", 0.01], ["NICKEL", 0], ["DIME", 0], ["QUARTER", 0], ["ONE", 1.00], ["FIVE", 0], ["TEN", 0], ["TWENTY", 0], ["ONE HUNDRED", 0]]);