OJ Board

I've tested those sample I/Os from http://acm.uva.es/p/v109/10900.html,
and the results are ok.
Someone can give me some I/Os ? thanks!


Input My output
n=10 t=0.6 109.951
n=25 t=0.2 109.514
n=30 t=1 1073741824.000
n=30 t=0 0.000
n=30 t=0.99 923830472.267
n=2 t=1 4.000

thank you,mf.

I try to solve this problem with Combinatorial Math, but get WA.
My method is below
1. input n and k // x1+x2+x3+...+xk = n
2. compute the value of C(n+k-1,n) //C is the binomial coefficient
3. output

when I input
100 1 //output 1
100 2 //output 101
100 3 //output 5151
100 4 //output 176851 ...