2015年03月09日 蛋炒饭

[think2011]

你是一家快餐店的老板，每天营业前，你需要根据采购的食材来确定今天能够做多少份快餐：

// 炒蛋饭食谱
var fryRice = {
    rice: 1,
    egg: 1,
    meat: 2
}

// 食材
var material = {
    rice: 10,     // 100
    egg: 10,     // 100
    meat: 5     // 50
}

function check (food, material) {
    // 请完成这个代码
}

console.log(check(fryRice, material)); 
// 结果： {sum: 2, remnants: {rice: 8, egg: 8, meat: 1}}

[LetroLiu]

    var obj={},
        remnants={},
        o,
        i=0;
    for(o in food){
        i=material[o];
        break;
    }
    for(o in food){
        obj[o]=parseInt(material[o]/food[o]);
        i=i>obj[o]?obj[o]:i;
    }
    for(o in food){
        remnants[o]=material[o]-food[o]*i;
    }
    return {sum:i,remnants:remnants};

[XadillaX]

function check (food, material) {
    return (function(v) {
        return { sum: v, remnants: Object.keys(food).reduce(function(res, i) {
            return res[i] = material[i] - v * food[i], res;
        }, {}) };
    })(Object.keys(food).reduce(function(res, i) {
        return Math.min(res, parseInt(material[i] / food[i]));
    }, Number.MAX_VALUE));
}

还是老风格，不带 if，for 和 var。

[VaJoy]

    function check (food, material) {
      var flag = !1,
          sum = 0,
          remnants = {};
      Object.keys(food).forEach(function(key){
        if(!material[key]||material[key]<food[key]) flag=!0;
        sum = !sum?((material[key]/food[key])|0):Math.min(sum,(material[key]/food[key])|0);
      });
      if(flag) return {sum:0,remnants:material};
      Object.keys(material).forEach(function(key){
        remnants[key] = material[key] - sum*(food[key]||0)
      });
      return {sum:sum,remnants:remnants}
    }

才发现在forEach里return的话是不会终止函数甚至不会终止循环的，还不如用一楼的for in

[VaJoy]

ES6来帮忙，这样效率高一点，sum=0的时候直接return不再执行

function check (food, material) {
    var sum = 0,
        remnants = {};
    for(var key of Object.keys(food)){
        if(!material[key]||material[key]<food[key]) return {sum:0,remnants:material};
        sum = !sum?((material[key]/food[key])|0):Math.min(sum,(material[key]/food[key])|0);
    }
    Object.keys(material).forEach(function(key){
        remnants[key] = material[key] - sum*(food[key]||0)
    });
    return {sum:sum,remnants:remnants}
}

[think2011]

@VaJoy 咦，哪里用到了ES6的特性，感兴趣！

[VaJoy]

@think2011 for of

[lichengzhou]

弄一个不太好的：

function check (food, material) {
    // 请完成这个代码
   var sum = null;
    for(var prop in material){
      if(material.hasOwnProperty(prop) && food[prop]){
        var temp = parseInt(material[prop]/food[prop]);
        sum =  sum == null? temp: (temp > sum ? sum : temp);
      }
    }

    var remnants = {};
   for(var prop in material){
      if(material.hasOwnProperty(prop)){
        remnants[prop] = material[prop] - (food[prop] ? food[prop]*sum : 0);
      }
    }

    return {
      sum: sum,
      remnants: remnants
    };
}

[PeakFish]

来个递归版

function check (food, material) {
    // 请完成这个代码
    var sum = 0;
    function reducematerial(material){
      if(material.rice < 1 || material.egg < 1 || material.meat < 2){
        return;
      }else{
        ++sum;
        material.rice -= 1;
        material.egg -= 1;
        material.meat -= 2;
        reducematerial(material);
      }
    }
    reducematerial(material);
    return {sum: sum, remnants: material};
}