UVa 369 - Combinations

　　题目大意：给两个数n, m，求C(n, m)。用java直接写就好了。

 1 import java.io.*;
 2 import java.util.*;
 3 import java.math.*;
 4 
 5 class Main
 6 {
 7     public static void main(String[] args)
 8     {
 9         Scanner sc = new Scanner(System.in);
10         BigInteger[] fact = new BigInteger[110];
11         fact[0] = BigInteger.ONE;
12         for (int i = 1; i <= 100; i++)
13             fact[i] = fact[i-1].multiply(BigInteger.valueOf(i));
14         int n, m;
15         while (sc.hasNext())
16         {
17             n = sc.nextInt();
18             m = sc.nextInt();
19             if (n == 0 && m == 0)  break;
20             BigInteger ans = fact[n].divide(fact[m]).divide(fact[n-m]);
21             System.out.println(n + " things taken " + m + " at a time is " + ans + " exactly.");
22         }
23 
24     }
25 }
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posted @ 2013-10-01 18:39  xiaobaibuhei  阅读(371)  评论(0)    收藏  举报