I use res:array[0..250001] of integer keeping four digits in each
element of array (in one integer I keep numbers from 0 to 9999 - four
digits). In total I use 250002 * 2 = 500004 bytes (500004 / 1024 =
489K) - it's less then 1000K, but in online status I see that my
program uses 1052K. What's the matter?

Here is my all part of variable definition:

const mx = 250001;
var am,temp,cur,i,j,n:longint;
    res:array[0..mx] of integer;
    carry,k,l,a,b:word;

Ok, tell me, please to medv@roller.ukma.kiev.ua how to solve this
problem without arrays.

because Pascal compiler here is Delphi, sizeof(Integer) = 4

> I use res:array[0..250001] of integer keeping four digits in each
> element of array (in one integer I keep numbers from 0 to 9999 -
four
> digits). In total I use 250002 * 2 = 500004 bytes (500004 / 1024 =
> 489K) - it's less then 1000K, but in online status I see that my
> program uses 1052K. What's the matter?
>
> Here is my all part of variable definition:
>
> const mx = 250001;
> var am,temp,cur,i,j,n:longint;
>     res:array[0..mx] of integer;
>     carry,k,l,a,b:word;
>
> Ok, tell me, please to medv@roller.ukma.kiev.ua how to solve this
> problem without arrays.
>
>

Usually i write:
type
  integer = -32767..32768;

Good luck!