农夫养牛问题几种解法源码

package three; import java.util.ArrayList; import java.util.List; public class Cow { private int age; public Cow(){ age = 0; } public Cow play(){ age ++; return age > 3 ? new Cow():null; } public static void main(String[] args) { List<Cow> list = new ArrayList<Cow>(); list.add(new Cow()); for(int i = 0; i <= 10;i++){ for(int j =0;j<list.size();j++){ Cow cow = list.get(j).play(); if(cow != null) list.add(cow); } } System.out.println("10年后，共有：" + list.size()); } }