题解 | #汽水瓶#

简单递归

public class Main{
	public static void main(String[] args){		Scanner sc = new Scanner(System.in);
		int num;
		while((num=sc.nextInt())!=0){
			System.out.println(drink(num));
		}
	}
	public static int drink(int num){
		int count = 0;
		if(num <= 1){
			return 0;
		}
		else if(num == 2){
			return 1;
		}
		else{
			count += num/3;
			return count+drink(num%3+count);
		}
	}
}