java實現權重隨機演算法
阿新 • • 發佈:2018-12-08
權重隨機演算法在抽獎,資源排程等系統中應用還是比較廣泛的,一個簡單的按照權重來隨機的實現,權重為幾個隨機物件(分類)的命中的比例,權重設定越高命中越容易,之和可以不等於100;
import java.util.ArrayList; import java.util.List; import java.util.Random; public class WeightRandom { static List<WeightCategory> categorys = new ArrayList<WeightCategory>(); private static Random random = new Random(); public static void initData() { WeightCategory wc1 = new WeightCategory("A",60); WeightCategory wc2 = new WeightCategory("B",20); WeightCategory wc3 = new WeightCategory("C",20); categorys.add(wc1); categorys.add(wc2); categorys.add(wc3); } public static void main(String[] args) { initData(); Integer weightSum = 0; for (WeightCategory wc : categorys) { weightSum += wc.getWeight(); } if (weightSum <= 0) { System.err.println("Error: weightSum=" + weightSum.toString()); return; } Integer n = random.nextInt(weightSum); // n in [0, weightSum) Integer m = 0; for (WeightCategory wc : categorys) { if (m <= n && n < m + wc.getWeight()) { System.out.println("This Random Category is "+wc.getCategory()); break; } m += wc.getWeight(); } } } class WeightCategory { private String category; private Integer weight; public WeightCategory() { super(); } public WeightCategory(String category, Integer weight) { super(); this.setCategory(category); this.setWeight(weight); } public Integer getWeight() { return weight; } public void setWeight(Integer weight) { this.weight = weight; } public String getCategory() { return category; } public void setCategory(String category) { this.category = category; } }