Edited by author 21.08.2008 15:52

this forum is very very good.It helps us learns how to develop
good test data.I used this forum to solve the problem.Very good test data.Excellent.It has checked the problem in many ways.Especially this problem is very good.Even though the logic is easy there were very good test data

Edited by author 16.06.2008 16:00

just use a stack to hold s2.

Try this test:
aaaabbbb

Please give me test №3.

Help please!

I want to take TL not WA ^) In what problem?
All Tests on this forum i have already tested.

Thanks for your help.

Have somebody wrong answer on this test?

I keep getting WA#4 for this problem.
I read all the threads and tried all the test data.
I get correct answer for all the test data on my computer but not on the judge.
On one of the threads it was given that test 4 has test
data: 2101221012
I got the answer as 210122101221012 but I still get WA#4.
Can anyone help me??

not only in this problem. what can i use the KMP algorithm for? what kind of problems can i solve?

There is a quite stupid algorithm, but You must to take maximum input value increase a bit. I change 10000 on 20000 an got AC! It's quite strange :( About two hour in this night a spend to check this bug :(

Help me, please.
I shall be very grateful. HELP!!!!!!!!!!!!!!!!

Try this test:
a

Right answer is: aa

 - Good luck.

Edited by author 01.02.2006 02:20

For test 'aba' right answer is 'ababa'
'saaasaaas'-> 'saaasaaasaaas'
'aa'->'aaa'
'babab'->'bababab'
'a'->'aa'
Good luck!

Edited by author 24.01.2006 15:42

type kir=array[1..10000] of char;
var
m:kir;
y,u,t,e,q,i,w:longint;
r,ch:char;
f2,f1:text;
begin

assign(f1,'input.txt');
reset(f1);
i:=0;
read(f1,r);
while r in ['a'..'z','A'..'Z','0'..'9'] do begin
inc(i);
m[i]:=r;
read(f1,r);
end;
close(f1);
q:=i;

w:=q div 2;
for i:=q-1 downto w do
  begin  u:=0;
  for e:=1 to q-i do
    begin
    if m[i-e]=m[i+e] then  inc(u)
    else  break;
    end;
   if (u>t) and (e=q-i) then begin t:=u;y:=i;end;
  end;

  if t<>0 then begin u:=y-t-1;
                     for i:=1 to u do m[q+i]:=m[u-i+1];
                     q:=q+u;
                     end
          else begin for i:=1 to q do
          m[q+i-1]:=m[q-i+1];
          q:=q*2-1;
          end;
i:=1;
assign(f2,'output.txt');
rewrite(f2);
while i<=q do begin
 write(f2,m[i]);
 inc(i);
 end;
 close(f2);
  end.

My code:
-----------------------------------------------------------

program Task;

{$APPTYPE CONSOLE}

{ Task #1354 }

var s1: AnsiString;
    s2: AnsiString;

function IsPalindrom(S: AnsiString): Boolean;
var      i: integer;
begin
     IsPalindrom := True;
     for i := 1 to length(S) div 2 do
         if S[i] <> S[length(S) - i + 1] then
            begin
                 IsPalindrom := False;
                 break;
            end;
end;

function Revert(S: AnsiString): AnsiString;
var      i: integer;
         t: AnsiString;
begin
     t := '';
     for i := 1 to length(S) do
         t := t + S[length(s) - i + 1];
     Revert := t;
end;

var i:  integer;
    stop: boolean;

begin
     Readln(s1);
     stop := false;
     i := 2;
     while not stop and (i <= length(s1)) do
           begin
                if IsPalindrom(Copy(s1,i,length(s1) - i + 1)) then
                   begin
                        s2 := Revert(Copy(s1,1,i - 1));
                        stop := true;
                   end
                else
                    inc(i);
           end;
     writeln(s1 + s2);
end.

-----------------------------------------------------------
I get Wrong Answer, but I think that my solution all right. WHY??
[Sorry for my bad English]
P.S. AnsiString can consist 10000 symbols

Edited by author 04.11.2005 11:40

{Why?}
var S: string;
    ns: String;
    i: integer;
    j: integer;

function Palindrom(st: string): boolean;
var      i: integer;
         b: boolean;
begin
     b:=true;
     i:=1;
     while (i<=length(s) div 2) and b do
           begin
                if st[i]<>st[length(st)-i+1] then b:=false;
                inc(i);
           end;
     Palindrom:=b;
end;

function Revert(st: string): string;
var temp: string;
    i: integer;
begin
     temp:='';
     for i:=length(st) downto 1 do
         temp:=temp+st[i];
     revert:=temp;
end;

begin
     readln(s);
     i:=0;
     for j:=length(s)-2 downto 1 do
         if palindrom(Copy(s,j,length(s)-j+1)) then i:=j;
     if i=0 then
        begin
             ns:=Revert(Copy(s,1,length(s)-1));
             writeln(s+ns);
        end else
     if i=1 then writeln(s+Copy(s,2,length(s)-1)) else
        begin
             ns:=Revert(Copy(s,1,i-1));
             writeln(s+ns);
        end;
end.