My solution is :

A[0,0] := 1 ;
For i := 1 to n do Begin
    A[i] := A[i-1] ;
    For p := 1 to (S div 2) do
        For j := 1 to 9 do
            if p >= j then A[i,p] := A[i,p] + A[i-1,p-j];
End ;

Writeln( A[n,S div 2] * A[n,S div 2]) ;

I think it's Ok ! But WA test#6 ! Help me please !

I think your mistake is calculation !
( Sorry , My English is not good ! )

Edited by author 21.06.2005 10:07

You need to use long arithmetics because longest answer is 50 digits.

Try:

n=3
k=1

Answer is 0!