关于随机

来源：互联网发布：淘宝图片授权管理编辑：程序博客网时间：2024/04/29 12:56

首先,几率在游戏内广泛应用.虽然一次计算几率的系统消耗不大,但大量的调用消耗还是不容忽视的;

本例子适用于固定实例的多次随机(例如怪物掉落);

掉落模式:1.独立随机;2.小组随机;

独立随机:每个随机子都是由各自设定的随机几率独立的随机int res = new Random().nextInt(baseNum);根据res决定掉落

小组随机:（本例实现一组随机子产生一个结果的情况）,组内每个随机子都有自己的几率,类似每个随机子都有一个掉落的权值,掉落根据各个随机子的相对几率产生;

首先是配置:

/** * 几率相关配置 * @author Ka!ser. */public interface KRandomConfig {/** * 随机基数考虑做成配置 */static int rateBase = 10000;enum RateType implements EnumI {INTEGER(0,"整数几率",rateBase + "以内整数形式"),DOUBLE(1,"小数几率",String.valueOf(((double)1 / rateBase)).replaceAll("//d", "x").replace("x.", "0.") + "形式");private int value;private String name;private String des;RateType(int value,String name,String des) {this.value = value;this.name = name;this.des = des;}@Overridepublic String getDes() {return this.des;}@Overridepublic String getName() {return this.name;}@Overridepublic int getValue() {return this.value;}}enum RandomType implements EnumI {allRandom(0,"各自独立随机","互不干扰"),groupRandom(1,"分组随机","每组必出1个结果"),;private int value;private String name;private String des;RandomType(int value, String name, String des) {this.value = value;this.name = name;this.des = des;}@Overridepublic String getDes() {return des;}@Overridepublic String getName() {return name;}@Overridepublic int getValue() {return value;}}}

/** * 随机实例 * * @author Ka!ser. */public abstract class KRandom implements KRandomConfig {/** * 几率 */int[] rates;public static Random RANDOM = new Random();/** * 获取随机结果对应几率数组的index * * @return */public abstract List<Integer> getResultIndex();public abstract String getInfo();/** * 获得实例 * * @author: Ka!ser * @param type * @param rates * @param rateType * @return KRandom */public static KRandom getInstance(RandomType type, double[] rates) {switch (type) {case allRandom:return new KAllRandom(rates);case groupRandom:return new KGroupRandom(rates);default:throw new IllegalStateException("初始化失败");}}/** * 获取随机对象的实例 * * @param type * @param rates * @param rateType * @return */public static KRandom getInstance(RandomType type, int[] rates,RateType rateType) {switch (type) {case allRandom:return new KAllRandom(rates);case groupRandom:return new KGroupRandom(rates);default:throw new IllegalStateException("初始化失败");}}/** * 修正几率针对小数型的几率,以10000作为基数（可做配置）,转化成整数.测试基数10000 故小数几率只能到万分为（0.XXXX） * * @author: Ka!ser * @return double[] */static int[] modifyDoubleRate(double[] rates) {int tempRateBase = rateBase;if (rates[0] > 1) {tempRateBase = 1;}int[] modifyRate = new int[rates.length];for (int i = rates.length - 1; i >= 0; --i) {modifyRate[i] = (int) (rates[i] * tempRateBase);}return modifyRate;}/** * 检查数据合法性 * * @author: Ka!ser * @time: 2011-2-16下午06:15:52 * @return boolean */public boolean check() {if (rates == null) {throw new IllegalStateException("初始化异常:null! rates:[" + rates + "]");}if (rates.length == 0) {throw new IllegalStateException("几率异常长度:0");}return true;}}

独立随机

分组随机实现如下

/** * * @author Ka!ser. 2011-2-15 */public class KGroupRandom extends KRandom {/* * 几率区间 */private int[] rateInterval = null;public KGroupRandom(double[] rates) {this(modifyDoubleRate(rates));}public KGroupRandom(int[] rates) {this.rates = rates;check();}@Overridepublic String getInfo() {return null;}@Overridepublic List<Integer> getResultIndex() {List<Integer> result = new ArrayList<Integer>();if (rates.length == 0) {throw new IllegalStateException("");}if (rateInterval == null) {modifyRate();}int rateResult = RANDOM.nextInt(rateInterval[rateInterval.length - 1]);for (int i = 0; i < rateInterval.length; i++) {if (rateResult < rateInterval[i]) {result.add(i);return result;}}throw new IllegalStateException("");}/** * 针对分组随机产生区间段数组 * 例如: * 物品A 几率 1 * 物品B 几率 5 * 物品C 几率 2 * 生成的数组为{1,6,8} * @return */int[] modifyRate() {rateInterval = new int[rates.length];//rateInterval[0] = rates[0];for (int i = 1; i < rates.length; i++) {rateInterval[i] = rates[i] + rateInterval[i - 1];}return rateInterval;}}