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package com.util;
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import java.util.Collections;
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import java.util.List;
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import java.util.Random;
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//各种随机数生成
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public class RandomUtils {
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private static final Random random = new Random();
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//生成[min, max]范围内的随机整数（包含边界）
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public static int nextInt(int min, int max) {
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if (min > max) {
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throw new IllegalArgumentException("min不能大于max");
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}
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return min + random.nextInt(max - min + 1);
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}
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//从数组中随机选择一个元素(模板类）
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public static <T> T randomChoice(T[] array) {
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if (array == null || array.length == 0) {
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throw new IllegalArgumentException("数组不能为空");
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}
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return array[random.nextInt(array.length)];
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}
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//从列表中随机选择一个元素
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public static <T> T randomChoice(List<T> list) {
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if (list == null || list.isEmpty()) {
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throw new IllegalArgumentException("列表不能为空");
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}
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return list.get(random.nextInt(list.size()));
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}
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/**
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* 打乱列表顺序
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* @param list 要打乱的列表
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*/
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public static <T> void shuffle(List<T> list) {
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Collections.shuffle(list, random);
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}
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//生成指定范围内的随机双精度浮点数
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public static double nextDouble(double min, double max) {
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if (min > max) {
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throw new IllegalArgumentException("min不能大于max");
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}
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return min + (max - min) * random.nextDouble();
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}
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//生成随机布尔值
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public static boolean nextBoolean() {
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return random.nextBoolean();
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}
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//按概率返回true（题目生成概率）
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//示例：probability(0.7) 有70%概率返回true
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public static boolean probability(double probability) {
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if (probability < 0.0 || probability > 1.0) {
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throw new IllegalArgumentException("概率必须在0.0-1.0之间");
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}
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return random.nextDouble() < probability;
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}
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} |
