| New file |
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| | | package com.yami.trading.huobi.data; |
| | | |
| | | import java.math.BigDecimal; |
| | | import java.math.RoundingMode; |
| | | import java.util.ArrayList; |
| | | import java.util.List; |
| | | import java.util.Random; |
| | | |
| | | public class RandomNumbersGenerator { |
| | | |
| | | /** |
| | | * 生成多个有正有负的数,总和等于目标value |
| | | * @param target 目标总和(BigDecimal) |
| | | * @param count 生成的数字数量(至少为2) |
| | | * @param scale 小数位数(确保精度) |
| | | * @return 满足条件的数字列表 |
| | | */ |
| | | public static List<BigDecimal> generateNumbers(BigDecimal target, int count, int scale) { |
| | | // 校验参数:数量至少为2 |
| | | if (count < 2) { |
| | | throw new IllegalArgumentException("生成数量必须至少为2"); |
| | | } |
| | | |
| | | List<BigDecimal> numbers; |
| | | |
| | | // 计算target的20%(绝对值,作为最后一个数的阈值) |
| | | BigDecimal threshold = target.abs().multiply(new BigDecimal("0.2")).setScale(scale, RoundingMode.HALF_UP); |
| | | |
| | | do { |
| | | numbers = new ArrayList<>(count); |
| | | Random random = new Random(); |
| | | |
| | | // 步骤1:确定单个数字的最大绝对值范围(目标值的15%,可调整) |
| | | BigDecimal maxAbsValue = target.abs().multiply(new BigDecimal("0.15")); |
| | | if (maxAbsValue.compareTo(BigDecimal.ZERO) == 0) { |
| | | maxAbsValue = new BigDecimal("100"); // 目标为0时的默认范围 |
| | | } |
| | | |
| | | // 正数概率60% |
| | | double positiveProbability = 0.6; |
| | | |
| | | // 步骤2:生成前count-1个随机数 |
| | | for (int i = 0; i < count - 1; i++) { |
| | | BigDecimal randomValue = generateRandomValue(maxAbsValue, scale, random); |
| | | // 按概率设置正负 |
| | | if (random.nextDouble() >= positiveProbability) { |
| | | randomValue = randomValue.negate(); |
| | | } |
| | | numbers.add(randomValue); |
| | | } |
| | | |
| | | // 步骤3:计算最后一个数(确保总和为target) |
| | | BigDecimal sumPrev = numbers.stream().reduce(BigDecimal.ZERO, BigDecimal::add); |
| | | BigDecimal lastNum = target.subtract(sumPrev).setScale(scale, RoundingMode.HALF_UP); |
| | | numbers.add(lastNum); |
| | | |
| | | // 步骤4:确保有正有负 |
| | | ensureBothPositiveAndNegative(numbers, scale); |
| | | |
| | | // 检查最后一个数是否超过阈值:若lastNum的绝对值 > threshold,则重新生成 |
| | | } while (numbers.get(numbers.size() - 1).abs().compareTo(threshold) > 0); |
| | | |
| | | return numbers; |
| | | } |
| | | |
| | | /** |
| | | * 生成0到max之间的随机BigDecimal(指定小数位数,兼容Java 8+) |
| | | */ |
| | | private static BigDecimal generateRandomValue(BigDecimal max, int scale, Random random) { |
| | | // 将max转换为整数(放大10^scale倍),避免double精度问题 |
| | | BigDecimal scaleFactor = new BigDecimal(Math.pow(10, scale)).setScale(scale); |
| | | long maxLong = max.multiply(scaleFactor).setScale(0, RoundingMode.FLOOR).longValue(); |
| | | |
| | | // 兼容Java 8+的写法:生成[0, maxLong]范围内的随机long |
| | | long randomLong; |
| | | if (maxLong == 0) { |
| | | // 若最大值为0,直接返回0 |
| | | randomLong = 0; |
| | | } else { |
| | | // 生成[0, maxLong]的随机数(避免nextLong()的负数问题) |
| | | // 逻辑:(random.nextLong() % (maxLong + 1) + (maxLong + 1)) % (maxLong + 1) |
| | | long range = maxLong + 1; // 范围长度(0到maxLong共range个数字) |
| | | randomLong = (random.nextLong() % range + range) % range; |
| | | } |
| | | |
| | | // 转换回BigDecimal并缩小scaleFactor倍 |
| | | return new BigDecimal(randomLong).divide(scaleFactor, scale, RoundingMode.HALF_UP); |
| | | } |
| | | |
| | | /** |
| | | * 确保列表中既有正数也有负数,若不满足则调整 |
| | | */ |
| | | private static void ensureBothPositiveAndNegative(List<BigDecimal> numbers, int scale) { |
| | | boolean hasPositive = numbers.stream().anyMatch(num -> num.compareTo(BigDecimal.ZERO) > 0); |
| | | boolean hasNegative = numbers.stream().anyMatch(num -> num.compareTo(BigDecimal.ZERO) < 0); |
| | | |
| | | if (hasPositive && hasNegative) { |
| | | return; // 已满足条件,无需调整 |
| | | } |
| | | |
| | | // 若全为非负(可能有0),需要调整出一个负数 |
| | | if (!hasNegative) { |
| | | adjustToHaveNegative(numbers, scale); |
| | | } |
| | | // 若全为非正(可能有0),需要调整出一个正数 |
| | | else if (!hasPositive) { |
| | | adjustToHavePositive(numbers, scale); |
| | | } |
| | | } |
| | | |
| | | /** |
| | | * 当全为非负时,调整出一个负数(保持总和不变) |
| | | */ |
| | | private static void adjustToHaveNegative(List<BigDecimal> numbers, int scale) { |
| | | // 选第一个非零的数(避免调整0,否则还是0) |
| | | int idx = -1; |
| | | for (int i = 0; i < numbers.size(); i++) { |
| | | if (numbers.get(i).compareTo(BigDecimal.ZERO) > 0) { |
| | | idx = i; |
| | | break; |
| | | } |
| | | } |
| | | if (idx == -1) { |
| | | // 极端情况:全为0(目标值必为0),直接将第一个数设为1,最后一个设为-1 |
| | | numbers.set(0, new BigDecimal("1").setScale(scale)); |
| | | numbers.set(numbers.size() - 1, new BigDecimal("-1").setScale(scale)); |
| | | return; |
| | | } |
| | | |
| | | // 调整逻辑:将选中的数变为负数,同时将最后一个数加上2倍的原数(保持总和不变) |
| | | BigDecimal original = numbers.get(idx); |
| | | BigDecimal negative = original.negate(); |
| | | numbers.set(idx, negative); |
| | | |
| | | BigDecimal last = numbers.get(numbers.size() - 1); |
| | | BigDecimal adjustedLast = last.add(original.multiply(new BigDecimal("2"))) |
| | | .setScale(scale, RoundingMode.HALF_UP); |
| | | numbers.set(numbers.size() - 1, adjustedLast); |
| | | } |
| | | |
| | | /** |
| | | * 当全为非正时,调整出一个正数(保持总和不变) |
| | | */ |
| | | private static void adjustToHavePositive(List<BigDecimal> numbers, int scale) { |
| | | // 选第一个非零的数(避免调整0) |
| | | int idx = -1; |
| | | for (int i = 0; i < numbers.size(); i++) { |
| | | if (numbers.get(i).compareTo(BigDecimal.ZERO) < 0) { |
| | | idx = i; |
| | | break; |
| | | } |
| | | } |
| | | if (idx == -1) { |
| | | // 极端情况:全为0(目标值必为0),直接将第一个数设为1,最后一个设为-1 |
| | | numbers.set(0, new BigDecimal("1").setScale(scale)); |
| | | numbers.set(numbers.size() - 1, new BigDecimal("-1").setScale(scale)); |
| | | return; |
| | | } |
| | | |
| | | // 调整逻辑:将选中的数变为正数,同时将最后一个数减去2倍的原数(保持总和不变) |
| | | BigDecimal original = numbers.get(idx); |
| | | BigDecimal positive = original.negate(); |
| | | numbers.set(idx, positive); |
| | | |
| | | BigDecimal last = numbers.get(numbers.size() - 1); |
| | | BigDecimal adjustedLast = last.subtract(original.multiply(new BigDecimal("2"))) |
| | | .setScale(scale, RoundingMode.HALF_UP); |
| | | numbers.set(numbers.size() - 1, adjustedLast); |
| | | } |
| | | |
| | | |
| | | // 测试示例 |
| | | public static void main(String[] args) { |
| | | // 测试1:目标值为100,生成5个数,保留2位小数 |
| | | BigDecimal target1 = new BigDecimal("0.01"); |
| | | List<BigDecimal> result1 = generateNumbers(target1, 200/10, 10); |
| | | System.out.println("目标值:" + target1 + ",生成的数:" + result1); |
| | | System.out.println("总和:" + result1.stream().reduce(BigDecimal.ZERO, BigDecimal::add) + "\n"); |
| | | |
| | | } |
| | | } |