题解 | #统计每个月兔子的总数#

package edu.shanxi.practise.hj37;

import java.util.Scanner;

public class Main {

    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int day = sc.nextInt();//天数
        int mutu = 0;//母兔的数量
        int xiaotu1 = 1;//第一天小兔的数量
        int xiaotu2 = 0;//第二天小兔的数量
        for(int i = 1;i < day;i++) {
            mutu += xiaotu2;//小兔2长成母兔
            xiaotu2 = xiaotu1;//小兔1长成小兔2
            xiaotu1 = mutu;//母兔生出来小兔1
        }
        System.out.println(mutu + xiaotu1 + xiaotu2);
        sc.close();
    }

}