喝1000瓶水问题

题目如下：假设有N瓶水(当然N>0吧)
每喝一瓶后可以得到的一个空瓶子
而 每3个空瓶子又能换1瓶水，喝掉以后又得到一个空瓶子，

问题是，你总共能喝多少瓶水，最后还剩余多少个空瓶子？
假设有1000瓶水：

//非递归：
class Main1 {
public static void main(String[] args) {
int buttle;
int emptybuttle = 0;
int count = 0;

for (buttle = 1000; buttle != 0; buttle--) {
count++;
emptybuttle++;
if (emptybuttle == 3) {
emptybuttle = 0;
buttle++;
}
}
System.out.println(buttle);
System.out.println(emptybuttle);
System.out.println(count);

}
}

//递归：
class Main2 {
public static void main(String[] args) {
int buttle = 1000;
int emptybuttle = 0;
int count1 = 0;
System.out.println(count(emptybuttle, buttle, count1));

}
public static int count(int emptybuttle,int buttle,int count1){
if (buttle==0&&emptybuttle==2){
return count1;
}
if (emptybuttle == 3){
emptybuttle = 0;
buttle++;
}
return count(emptybuttle+1,buttle-1,count1+1);
}
}