2613：Choose and divide

题目描述

The binomial coefficient C(m,n) is defined as

            m!

C(m,n) = --------

         n!(m-n)!

Given four natural numbers p, q, r, and s, compute the the result of dividing C(p,q) by C(r,s).

输入解释

Input consists of a sequence of lines. Each line contains four non-negative integer numbers giving values for p, q, r, and s, respectively, separated by a single space. All the numbers will be smaller than 10,000 with p>=q and r>=s.

输出解释

For each line of input, print a single line containing a real number with 5 digits of precision in the fraction, giving the number as described above. You may assume the result is not greater than 100,000,000.

输入样例

10 5 14 9
93 45 84 59
145 95 143 92
995 487 996 488
2000 1000 1999 999
9998 4999 9996 4998

输出样例

0.12587
505606.46055
1.28223
0.48996
2.00000
3.99960

该题目是Virtual Judge题目，来自北京大学POJ

题目来源 Waterloo local 1999.10.02

源链接： POJ-2613

最后修改于 2020-10-29T06:37:12+00:00 由爬虫自动更新

共提交 0 次

通过率 --%

时间上限	内存上限
1000	65536