假设我想创造一个游戏.在游戏开始时,玩家将挑选一个怪物.
公平地挑选怪物很容易.
// get all monsters with equal chance
public Monster getMonsterFair(){
Monster[] monsters = {new GoldMonster(),new SilverMonster(),new BronzeMonster()};
int winIndex = random.nextInt(monsters.length);
return monsters[winIndex];
}
并不公平地挑选怪物.
// get monsters with unequal chance
public Monster getMonsterUnFair(){
double r = Math.random();
// about 10% to win the gold one
if (r < 0.1){
return new GoldMonster();
}
// about 30% to winthe silver one
else if ( r < 0.1 + 0.2){
return new SilverMonster();
}
// about 70% to win the bronze one
else {
return new BronzeMonster();
}
}
问题是,当我在游戏中添加一个新怪物时,我必须编辑if-else.
或者我将赢得GoldMonster的机会改为0.2,我必须将所有0.1改为0.2
这很难看,也不容易维护.
// get monsters with unequal change & special monster
public Monster getMonsterSpecial(){
double r = Math.random();
// about 10% to win the gold one
if (r < 0.1){
return new GoldMonster();
}
// about 30% to win the silver one
else if ( r < 0.1 + 0.2){
return new SilverMonster();
}
// about 50% to win the special one
else if ( r < 0.1 + 0.2 + 0.2){
return new SpecialMonster();
}
// about 50% to win the bronze one
else {
return new BronzeMonster();
}
}
解决方法
基本上是@Egor Skriptunoff所说的.这应该很容易扩展.你可以使用Class< Monster>的集合.如果你不想使用枚举.
enum Monster {
GOLD(1),SILVER(3),BRONZE(6) // pseudo probabilities
private int weight;
// constructor etc..
}
public Monster getMonsterSpecial() {
List<Monster> monsters = new ArrayList<>();
for(Monster monsterType : Monster.values()) {
monsters.addAll(Collections.nCopies(monsterType.getWeight(),monsterType));
}
int winIndex = random.nextInt(monsters.length);
return monsters.get(winIndex);
}
你也许可以使枚举怪物复数,并让它指向一个类<？延伸怪物>如果你还想实例化怪物类.我只是想让这个例子更加清晰.
