I have two different solutions and each of them gives me WA3 :(
First - naive, here it is:
-----------------------------------
read(s);
l:=length(s);
n:=1999;
if l < n then
          if n mod l <> 0 then
                           A:=n mod l
                          else
                           A:=l
         else
          A:=n;
while l <> 1 do
 begin
   delete(s,A,1);
   n1:=n-(l-A);
   dec(l);
   if l < n1 then
          if n1 mod l <> 0 then
                            A:=n1 mod l
                           else
                            A:=l
         else
          A:=n1;
 end;
case s[1] of
 '?': writeln('Yes');
 ' ': writeln('No');
 else writeln('No comments');
end;
readln;
end.
-----------------------------------

And the next one is recursive solution inspired by Josephus problem formula:
-----------------------------------
function Jo(l: longint): longint;
begin
  if l = 1 then
            Jo:=0
           else
            Jo:=(Jo(l-1)+n) mod l;
end;

begin
read(s);
l:=length(s);
n:=1999;
case s[Jo(l)+1] of
 '?': writeln('Yes');
 ' ': writeln('No');
 else writeln('No comments');
end;
readln;
end.
-----------------------------------

Please, help me with some tests information or tell me about my stupid bugs :)
Maybe I miss some cases?


Edited by author 12.09.2011 00:58