母牛的故事

参考代码:

import java.util.Scanner;

public class Main {

    public static void main(String[] args) {

        Scanner sc = new Scanner(System.in);

        while (sc.hasNext()) {

            int n = sc.nextInt();

            int [] a = new int[55];

            if (n == 0) {

                return;

            } else if (n > 54 || n < 1) {

                continue;

            }

            if(n == 1||n == 2||n == 3||n == 4) {

                a[n]=n;

            }

            else {

                a[1]=1;

                a[2]=2;

                a[3]=3;

                a[4]=4;

                for (int i = 5; i <= n; i++) {

                    a[i] = a[i - 1] + a[i - 3]; // 从第五年开始，每年的母牛数量等于前一年的数量加上三年前母牛所生的新母牛数量

                }

            }

            System.out.println(a[n]);

        }

    }

}