权重随机算法Java实现

importjava.util.ArrayList;
importjava.util.List;
importjava.util.Random;

publicclass WeightRandom {
staticList<WeightCategory>  categorys = newArrayList<WeightCategory>();
privatestatic Random random = newRandom();

publicstatic void initData() {
WeightCategory wc1 = newWeightCategory("A",60);
WeightCategory wc2 = newWeightCategory("B",20);
WeightCategory wc3 = newWeightCategory("C",20);
categorys.add(wc1);
categorys.add(wc2);
categorys.add(wc3);
}

publicstatic 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();
}

}

}

classWeightCategory {
privateString category;
privateInteger weight;

publicWeightCategory() {
super();
}

publicWeightCategory(String category, Integer weight) {
super();
this.setCategory(category);
this.setWeight(weight);
}

publicInteger getWeight() {
returnweight;
}

publicvoid setWeight(Integer weight) {
this.weight = weight;
}

publicString getCategory() {
returncategory;
}

publicvoid setCategory(String category) {
this.category = category;
}
}