It's ma prog and it works well, But I get WA at test 2...WHY???


Uses Math;
Var
  x,y:array[1..1000] of char;
  T:array[0..1000,0..1000] of integer;
  i,j,n,z,d:integer;
BEGIN
  n:=1;
  read(x[n]);
  while (not Eoln) do begin inc(n); read(x[n]); end;

  for i:=0 to n do T[0,i]:=0;
  for i:=0 to n do T[i,0]:=0;
   FOR i:=1 to n do
    FOR j:=1 to n do
     if ord(x[i])=ord(x[n-j+1]) then T[i,j]:=T[i-1,j-1]+1
                                else T[i,j]:=max(T[i-1,j],T[i,j-1]);
  d:=T[n,n]; i:=n; j:=n; z:=1;
  while (d<>0) do
    begin
      while (T[i-1,j]=d) do DEC(i);
      while (T[i,j-1]=d) do DEC(j);
      y[z]:=x[i]; INC(z);
      DEC(i); DEC(j); DEC(d);
    end;
  for i:=z-1 downto 1 do write(y[i]);
END.

Edited by author 04.12.2008 01:13