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红包算法
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‎src/main/java/com/algorithm/study/demo/algorithm/MainDemo.java‎

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package com.algorithm.study.demo.algorithm;
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/**
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* @Author: liuxun
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* @CreateDate: 2018/11/8 下午1:50
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* @Version: 1.0
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*/
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public class MainDemo {
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public static void main(String[] args) {
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for (int i=0;i<100;i++){
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double redPacket = (Math.random() * (0.5 - 0.1) + 0.1);
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System.out.println(redPacket);
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}
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System.out.println((int)(Math.random()*0.9+0.1));
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}
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}

‎src/main/java/com/algorithm/study/demo/algorithm/RedPacket.java‎

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package com.algorithm.study.demo.algorithm;
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import java.util.LinkedList;
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import java.util.List;
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/**
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*
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* 模拟微信红包生成，以分为单位
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* @Author: liuxun
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* @CreateDate: 2018/11/8 下午2:22
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* @Version: 1.0
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*/
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public class RedPacket {
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/**
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* 生成红包最小值 1分
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*/
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private static final int MIN_MONEY = 1;
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/**
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* 生成红包最大值 200人民币
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*/
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private static final int MAX_MONEY = 200 * 100;
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/**
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* 小于最小值
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*/
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private static final int LESS = -1;
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/**
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* 大于最大值
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*/
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private static final int MORE = -2;
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/**
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* 正常值
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*/
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private static final int OK = 1;
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/**
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* 最大的红包是平均值的 TIMES 倍，防止某一次分配红包较大
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*/
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private static final double TIMES = 2.1F;
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private int recursiveCount = 0;
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public List<Integer> splitRedPacket(int money, int count) {
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List<Integer> moneys = new LinkedList<>();
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//金额检查，如果最大红包 * 个数 < 总金额；则需要调大最小红包 MAX_MONEY
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if (MAX_MONEY * count <= money) {
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System.err.println("请调大最小红包金额 MAX_MONEY=[" + MAX_MONEY + "]");
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return moneys ;
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}
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//计算出最大红包
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int max = (int) ((money / count) * TIMES);
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max = max > MAX_MONEY ? MAX_MONEY : max;
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for (int i = 0; i < count; i++) {
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//随机获取红包
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int redPacket = randomRedPacket(money, MIN_MONEY, max, count - i);
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moneys.add(redPacket);
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//总金额每次减少
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money -= redPacket;
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}
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return moneys;
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}
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private int randomRedPacket(int totalMoney, int minMoney, int maxMoney, int count) {
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//只有一个红包直接返回
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if (count == 1) {
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return totalMoney;
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}
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if (minMoney == maxMoney) {
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return minMoney;
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}
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//如果最大金额大于了剩余金额 则用剩余金额 因为这个 money 每分配一次都会减小
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maxMoney = maxMoney > totalMoney ? totalMoney : maxMoney;
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//在 minMoney到maxMoney 生成一个随机红包
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int redPacket = (int) (Math.random() * (maxMoney - minMoney) + minMoney);
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int lastMoney = totalMoney - redPacket;
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int status = checkMoney(lastMoney, count - 1);
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//正常金额
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if (OK == status) {
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return redPacket;
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}
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//如果生成的金额不合法 则递归重新生成
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if (LESS == status) {
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recursiveCount++;
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System.out.println("recursiveCount==" + recursiveCount);
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return randomRedPacket(totalMoney, minMoney, redPacket, count);
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}
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if (MORE == status) {
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recursiveCount++;
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System.out.println("recursiveCount===" + recursiveCount);
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return randomRedPacket(totalMoney, redPacket, maxMoney, count);
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}
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return redPacket;
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}
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/**
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* 校验剩余的金额的平均值是否在 最小值和最大值这个范围内
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*
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* @param lastMoney
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* @param count
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* @return
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*/
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private int checkMoney(int lastMoney, int count) {
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double avg = lastMoney / count;
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if (avg < MIN_MONEY) {
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return LESS;
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}
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if (avg > MAX_MONEY) {
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return MORE;
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}
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return OK;
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}
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public static void main(String[] args) {
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RedPacket redPacket = new RedPacket();
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List<Integer> redPackets = redPacket.splitRedPacket(10, 10);
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System.out.println(redPackets);
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int sum = 0;
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for (Integer red : redPackets) {
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sum += red;
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}
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System.out.println(sum);
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}
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}

‎src/main/java/com/algorithm/study/demo/algorithm/ZumaProject.java‎

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String findInput=find(index,newInput);
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System.out.println("消除后的结果："+findInput);
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}
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public static String matcher(String input)
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{

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