微信红包的算法

public class Test {
	/***
	 * 红包数量
	 */
	public static int remainSize = 5;
	/**
	 * 红包金额
	 */
	public static double remainMoney = 1000;
	
	public static double getRandomMoney() {
		/**
		 * remainSize 剩余的红包数量
		 * remainMoney 剩余的钱
		 */
		//判断是否最后一个红包
		if (remainSize == 1) {
			remainSize --;
			return (double) Math.round(remainMoney * 100) / 100;
		}
		Random ran = new Random();
		//最小红包是1分钱
		double min = 0.01;
		//最大红包，剩余钱平均数的2倍
		double max = remainMoney / remainSize * 2;
		//在最小和最大红包之间产生一个随机数
		double money = ran.nextDouble() * max;
		money = money <= min ? 0.01 : money;
		money = Math.floor(money * 100) / 100;
		remainSize --;
		remainMoney -= money;
		return money;
	}

	public static void main(String[] args) {
		// TODO Auto-generated method stub
		int k = remainSize;
		for (int i = 0; i <  k; i++) {
			double money = Test.getRandomMoney();
			System.out.print(money + "\t");
		}
	}
}