题解 | #统计每个月兔子的总数#

import java.util.Scanner;

public class Main {

    //today--->当前月份；born--->出生月份；month--->养兔时间
    public static int produce(int born, int today, int month) {

        if (today <= month) {
            if (today - born >= 2) {
                //当前月份-出生月份 >= 2 ---->产一个崽，母兔+子兔+产下的一个崽
                return 1 + produce(born, today + 1, month)
                        + produce(today, today, month);
            } else
                //当前月份-出生月份 < 2 ---->不产崽
                return produce(born, today + 1, month);
        }
        return 0;
    }

    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        while (in.hasNextInt()) {
            int month = in.nextInt();
            //总的产崽数+最开始的基数兔(即兔子初始为1个)
            int sum = produce(1, 1, month) + 1;
            System.out.println(sum);
        }
    }
}