## 算法一：剩余金额随机法

// 分配红包的算法private static void testPocket(BigDecimal amount, BigDecimal min, BigDecimal num) {BigDecimal remain = amount.subtract(min.multiply(num));final Random random = new Random();final BigDecimal hundred = new BigDecimal("100");BigDecimal sum = BigDecimal.ZERO;BigDecimal redpeck ;for (int i = 0; i < num.intValue(); i++) {    final int nextInt = random.nextInt(100);    if (i == num.intValue() - 1) {        redpeck = remain;    } else {        redpeck = new BigDecimal(nextInt).multiply(remain).divide(hundred, 2, RoundingMode.FLOOR);    }    if (remain.compareTo(redpeck) > 0) {        remain = remain.subtract(redpeck);    } else {        remain = BigDecimal.ZERO;    }    sum = sum.add(min.add(redpeck));    System.out.println("第" + (i + 1) + "个人抢到红包金额为：" + min.add(redpeck).setScale(2, BigDecimal.ROUND_HALF_UP));}System.out.println("红包总额：" + sum.setScale(2, BigDecimal.ROUND_HALF_UP));}// 测试代码public static void main(String[] args) {    BigDecimal amount = new BigDecimal(100).setScale(2, BigDecimal.ROUND_HALF_UP);    BigDecimal min = new BigDecimal(0.01).setScale(2, BigDecimal.ROUND_HALF_UP);    BigDecimal num = new BigDecimal(10).setScale(2, BigDecimal.ROUND_HALF_UP);    testPocket2(amount,min,num);}

## 算法二：整体随机法

private static void testPocket2(BigDecimal amount,BigDecimal min ,BigDecimal num){    final Random random = new Random();    final int[] rand = new int[num.intValue()];    BigDecimal sum1 = BigDecimal.ZERO;    BigDecimal redpeck ;    int sum = 0;    for (int i = 0; i < num.intValue(); i++) {        rand[i] = random.nextInt(100);        sum += rand[i];    }    final BigDecimal bigDecimal = new BigDecimal(sum);    BigDecimal remain = amount.subtract(min.multiply(num));    for (int i = 0; i < rand.length; i++) {        if(i == num.intValue() -1){            redpeck = remain;        }else{            redpeck = remain.multiply(new BigDecimal(rand[i])).divide(bigDecimal,2,RoundingMode.FLOOR);        }        if(remain.compareTo(redpeck) > 0){            remain = remain.subtract(redpeck);        }else{            remain = BigDecimal.ZERO;        }        sum1= sum1.add(min.add(redpeck)).setScale(2, BigDecimal.ROUND_HALF_UP);        System.out.println("第"+(i+1)+"个人抢到红包金额为："+min.add(redpeck).setScale(2, BigDecimal.ROUND_HALF_UP));    }    System.out.println("红包总额："+sum1);}// 测试代码public static void main(String[] args) {    BigDecimal amount = new BigDecimal(100).setScale(2, BigDecimal.ROUND_HALF_UP);    BigDecimal min = new BigDecimal(0.01).setScale(2, BigDecimal.ROUND_HALF_UP);    BigDecimal num = new BigDecimal(10).setScale(2, BigDecimal.ROUND_HALF_UP);    testPocket2(amount,min,num);}

## 算法三：割线法

private static void testPocket3(BigDecimal amount, BigDecimal min, BigDecimal num) {    final Random random = new Random();    final int[] rand = new int[num.intValue()];    BigDecimal sum1 = BigDecimal.ZERO;    BigDecimal redpeck;    int sum = 0;    for (int i = 0; i < num.intValue(); i++) {        rand[i] = random.nextInt(100);        sum += rand[i];    }    final BigDecimal bigDecimal = new BigDecimal(sum);    BigDecimal remain = amount.subtract(min.multiply(num));    for (int i = 0; i < rand.length; i++) {        if (i == num.intValue() - 1) {            redpeck = remain;        } else {            redpeck = remain.multiply(new BigDecimal(rand[i]))                .divide(bigDecimal, 2, RoundingMode.FLOOR);        }        if (remain.compareTo(redpeck) > 0) {            remain = remain.subtract(redpeck).setScale(2, BigDecimal.ROUND_HALF_UP);        } else {            remain = BigDecimal.ZERO;        }        sum1 = sum1.add(min.add(redpeck).setScale(2, BigDecimal.ROUND_HALF_UP));        System.out.println("第" + (i + 1) + "个人抢到红包金额为：" + min.add(redpeck));    }    System.out.println("红包总额：" + sum1);}// 测试代码public static void main(String[] args) {    BigDecimal amount = new BigDecimal(100).setScale(2, BigDecimal.ROUND_HALF_UP);    BigDecimal min = new BigDecimal(0.01).setScale(2, BigDecimal.ROUND_HALF_UP);    BigDecimal num = new BigDecimal(10).setScale(2, BigDecimal.ROUND_HALF_UP);    testPocket2(amount,min,num);}

## 算法四：二倍均值法

BigDecimal remain = amount.subtract(min.multiply(num));    final Random random = new Random();    final BigDecimal hundred = new BigDecimal("100");    final BigDecimal two = new BigDecimal("2");    BigDecimal sum = BigDecimal.ZERO;    BigDecimal redpeck;    for (int i = 0; i < num.intValue(); i++) {        final int nextInt = random.nextInt(100);        if(i == num.intValue() -1){            redpeck = remain;        }else{            redpeck = new BigDecimal(nextInt).multiply(remain.multiply(two).divide(num.subtract(new BigDecimal(i)),2,RoundingMode.CEILING)).divide(hundred,2, RoundingMode.FLOOR);        }        if(remain.compareTo(redpeck) > 0){            remain = remain.subtract(redpeck).setScale(2, BigDecimal.ROUND_HALF_UP);        }else{            remain = BigDecimal.ZERO;        }        sum = sum.add(min.add(redpeck)).setScale(2, BigDecimal.ROUND_HALF_UP);        System.out.println("第"+(i+1)+"个人抢到红包金额为："+min.add(redpeck));    }    System.out.println("红包总额：" + sum);}