Please, help me! I've already posted this question, but nobody
answered. Why can't I get AC for this problem? I've already been sent
a correct solution, and I couldn't find a test for which our programs
give different results! Please, help me!

{$N+}
Program AB;
 Const Max=31;
 Var x,y,n:Extended;
     a:Array[0..32] Of Extended;
     cc:Array[0..Max,0..Max] Of Extended;
     mx,i,j,k,b:Longint;
 Function Fac(a:Longint):Extended;
  Var i:Longint;
      r:Extended;
 Begin
  r:=1;
  For i:=1 To a Do
   r:=r*i;
  Fac:=r;
 End;
 Function C(n,k:Longint):Extended;
  Var a:Extended;
 Begin
  If cc[n,k]>=0 Then
    c:=cc[n,k]
  Else Begin
   If k>n Then Begin
    cc[n,k]:=0;
    C:=0;
   End Else Begin
    If ((n=0) Or (k=0)) Then Begin
     cc[n,k]:=1;
     C:=1;
    End Else Begin
     cc[n,k]:=C(n-1,k)+C(n-1,k-1);
     C:=cc[n,k];
    End;
   End;
  End;
 End;
 Function f(x:Extended; k,mx:Longint):Extended;
  Var i:Longint;
      s:Extended;
 Begin
{  Writeln('x=',x:0:0,' k=',k); Readln;}
  If x=0 Then Begin
   If k=0 Then
    f:=1
   Else
    f:=0;
   Exit;
  End;
  s:=0;
  If k=1 Then Begin
   i:=-1;
   For i:=0 To mx-1 Do
    If a[i+1]>x Then
     Break;
   f:=i+1;
   Exit;
  End;
  For i:=0 To mx-1 Do
   If a[i+1]<=x Then Begin
    s:=s+C(i,k-1);
   End Else Begin
    s:=s+f(x-a[i],k-1,i);
    Break;
   End;
  f:=s;
 End;
Begin
{ Assign(input,'1057.in'); Reset(input);}
 For i:=0 To Max Do
  For j:=0 To Max Do
   cc[i,j]:=-1;
 For i:=0 To Max Do
  For j:=0 To Max Do
   c(i,j);
 Read(x,y,k,b);
 a[0]:=1;
 mx:=32;
 For i:=1 To 32 Do Begin
  a[i]:=a[i-1]*b;
  If a[i]>1E11 Then Begin
   mx:=i;
   Break;
  End;
 End;
 Writeln(f(y,k,mx)-f(x-1,k,mx):0:0);
End.

Have a look at your mail box.
Perhaps that will help you.
Good luck!