题解 | #放苹果#

import java.util.*;
//把m个同样的苹果放在n个同样的盘子里，允许有的盘子空着不放，问共有多少种不同的分法

public class Main {
    public static void main(String[] args) throws Exception {
        Scanner in = new Scanner(System.in);
        while (in.hasNext()) { // 注意 while 处理多个 case
            int apple = in.nextInt();
            int p = in.nextInt();
            System.out.println(v(apple, p));
        }
    }

    public static int v(int apple, int p) {
        if (p <= 0 || apple < 0) return 0;
        if (p == 1 || apple == 0 || apple == 1) return 1;

        return v(apple, p - 1) + v(apple - p, p);
    }
}