题目描述 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?
http://www.nowcoder.com/practice/a96b78e871c347bbb8cadf7bea0ee862?tpId=40&tqId=21395&rp=1&ru=/ta/kaoyan&qru=/ta/kaoyan/question-ranking
思路:
N个盘子放M个分两个互斥的情况
①没有盘子放0个,每个盘子至少1个,等于N个盘子放M-N个
②有盘子放0个,等于N-1个盘子放M个
package com.tonyluis.oj; import java.util.*; public class Main { public static void main(String[] args) { @SuppressWarnings("resource") Scanner in = new Scanner(System.in); while (in.hasNext()) { int apple = in.nextInt(); int cup = in.nextInt(); System.out.println(calc(apple, cup)); } } static int calc(int apple, int cup) { if (apple < 0) return 0; else if (apple <= 1 || cup == 1) return 1; return calc(apple, cup - 1) + calc(apple - cup, cup); } }
时间: 2024-10-13 09:58:30