4159：Indomie

题目描述

During recession, Amjad needs to queue for SembakoPlus. Sembako, as we all know, stands for “Sembilan Bahan Pokok” which consists of 9 kinds of item: Rice, Sugar, Cooking-oil,Meat, Egg, Milk, Corn, Kerosene and Iodized Salt. SembakoPlus consists of Sembako and one more item: Indomie! Amjad’s favorite of all time!! (therefore, no wonder why he could stand for this long queue).
Each person in the queue is allowed to pick only one item. No need to ask, Amjad wants only Indomie. Unfortunately, they are running out of SembakoPlus stock and currently there are three kinds of item left: Rice, Sugar and Indomie. As he could see from afar, he is quite sure that Rice and Sugar will be enough for everybody.
Given the number of remaining Indomie and the number of people queuing in front of Amjad, your task is to count the probability that he will get his Indomie. Amjad can’t do programming right now as he is very nervous so he can’t think logically. He needs your help!

输入解释

There will be multiple test cases for this problem. Each test case contains two integers N (1 ≤ N ≤ 50) and S (0 ≤ S ≤ 50), where N is the number of people queuing in front of Amjad and S is the remaining number of Indomie.

输出解释

For each case, print in a single line the probability in percentage that he will get his Indomie with 5 digits precision (he’s being paranoid)

输入样例

输出样例

提示

Explanation for 1st sample test case:
There are two peoples queuing in front of Amjad, so those two peoples could pick of the
following combination {1st people, 2nd people}:
1. Rice, Rice
2. Rice, Sugar
3. Rice, Indomie
4. Sugar, Rice
5. Sugar, Sugar
6. Sugar, Indomie
7. Indomie, Rice
8. Indomie, Sugar
Since there is only one Indomie left, there are only 4 out of 8 combinations that ensure Amjad
to get his Indomie (1, 2, 4 and 5), hence the probability is 4/8 = 50%.

来自杭电HDUOJ的附加信息

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该题目是Virtual Judge题目，来自杭电HDUOJ

题目来源 The 2011 Syrian Collegiate Programming Contest

源链接： HDU-4159

最后修改于 2020-10-25T23:10:49+00:00 由爬虫自动更新

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通过率 --%

时间上限	内存上限
2000/1000MS(Java/Others)	32768/32768K(Java/Others)