Java抽奖算法

时间:2022-05-28 小虚竹人气:0

一、题目描述

题目：小虚竹为了给粉丝送福利，决定在参与学习打卡活动的粉丝中抽一位幸运粉丝，送份小礼物。为了公平，要保证抽奖过程是随机的。

二、解题思路

1、把参与的人员加到集合中

2、使用Random对象获取随机数

3、把随机数当下标，获取集合中的幸运用户

三、代码详解

public class Basics28 {
    public static void main(String[] args) {
        List<String> luckUserNames = getLuckUserNames();
        Random random = new Random();
        int luckNum = random.nextInt(6);
        System.out.println("幸运的未来大佬是："+luckUserNames.get(luckNum));
    }

    private static List<String> getLuckUserNames(){
        List<String> luckUserNames = new ArrayList<String>();

        luckUserNames.add("李慢慢_");
        luckUserNames.add("TryAgain-");
        luckUserNames.add("team_dog");
        luckUserNames.add("Jasonakeke");
        luckUserNames.add("学好c语言的小王同学");
        luckUserNames.add("Ara～追着风跑");
        return luckUserNames;
    }
}

四、优化抽奖算法

解题思路

随机次数太少，需要优化

需要列出所有人随机命中的次数，显示出来，比较公开公平

代码详解

public class LuckDraw {
    public static void main(String[] args) {
        List<String> luckUserNames = getLuckUserNames();
        Random random = new Random();
        //key:luckNum ,value:count 
        Map<Integer,Integer> luckNumMap = new HashMap<Integer, Integer>();
        for (int i = 0; i < 100; i++) {
            int luckNum = random.nextInt(4);
            Integer count = luckNumMap.get(luckNum);
            if(count==null){
                count = 0;
            }
            ++count;
            luckNumMap.put(luckNum,count);
        }
        Integer maxLuckNum = 0;
        Integer maxCount =0;
        for(Integer luckNum:luckNumMap.keySet()){
            if(maxCount<luckNumMap.get(luckNum)){
                maxCount =  luckNumMap.get(luckNum);
                maxLuckNum = luckNum;
            }
            System.out.println(luckUserNames.get(luckNum)+"同学的幸运值："+luckNumMap.get(luckNum));
        }
        System.out.println("本周学习打卡积分第一且是幸运的未来大佬是："+luckUserNames.get(maxLuckNum));
        
    }
    
    private static List<String> getLuckUserNames(){
        List<String> luckUserNames = new ArrayList<String>();
        luckUserNames.add("学好c语言的小王同学");
        luckUserNames.add("Ara～追着风跑");
        luckUserNames.add("李慢慢_");
        luckUserNames.add("Jasonakeke");
        return luckUserNames;
    }
}

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