微信抢红包算法

 

微信抢红包算法： 

 

package test;

import java.util.Random;

import java.util.Scanner;

public class WeXinRedPakage {

public static void main(String[] args) {

RedPackage redPackage = new RedPackage();

Scanner scanner = new Scanner(System.in);

//下面两步应该做校验

redPackage.setRemainSize(5);//scanner.nextInt()scanner.nextInt()

redPackage.setRemainMoney(6);

double money = 0;

scanner.close();

for (int i = 0; i < 6; i++) {//假设6个人抢

money = redPackage.getRandomMoney();

System.out.println(money);

}

}

}

class RedPackage{

private double remainSize;

private double remainMoney;

public double getRemainSize() {

return remainSize;

}

public void setRemainSize(int remainSize) {

this.remainSize = remainSize;

}

public double getRemainMoney() {

return remainMoney;

}

public void setRemainMoney(int remainMoney) {

this.remainMoney = remainMoney;

}

public  double getRandomMoney() {

        // remainSize 剩余的红包数量

        // remainMoney 剩余的钱

if (this.getRemainSize()<1) {

System.out.println("_______");

return 0;

}

        if (this.remainSize == 1) {

        remainSize--;

        double money = Math.round(remainMoney * 100);

            return (money / 100);

        }

        Random r     = new Random();

        double min   = 0.01; //

        double max   = remainMoney / remainSize * 2;

        double money = r.nextDouble() * max;

        money = money > min ? money : min;

        money = Math.floor(money * 100) ;

        money = money/100;

        remainSize--;

        remainMoney -= money;

        System.out.println("-------------");

        return money;

    }

}

 顺便讲一下指定概率算法思路：

 1.按概率生成所有可能的结果放入容器

 2.使用一个随机数（在指定抽奖次数范围）去访问这个容器， 获得并移除容器这个值并返回

 3.抽奖一次操作一次，一直到到次数用完为止，这时候容器为零

 此算法还不完善，欢迎指点。