Help!!!

In problem 'Superlong Sums', i create program. It work correctly,
haven't 1000K of memory.
I posted program. Result was: 'Memory Limit Exceeded: 1398 K usage'...

At this moment, i create test account and posted program:
 program test;
 begin
 end.

Result is: '389 K usage'.
_______________________________________

Second program:
 program test;
 var arr:array[1..512000] of integer;
 begin
 end.

Result is: '389 K usage'.
________________________________________

Third program:
 program test;
 var arr:array[1..512000] of integer;
     i:longint;
 begin
 for i:=1 to 512000 do arr[i]:=1;
 end.

Result is: '2363 K usage'.
_________________________________________

I can't understand, what is happened?

This problem arise only in Pascal programs, IMHO: in ALL programs on
Pascal, memory usage>=389 K.
On C++, memory usage can be 0.
For example:

#include<math.h>
int main() {
 int i;
 int myarr[512001];
 i=1;
 while(i<512000) {
  myarr[i]=64000;
  i++;
 };
}

Memory usage is EIGHT KILOBYTE!!!
__________________________________
Second example:
#include<math.h>
int main() {
 int i;
 long int myarr[512001];
 i=1;
 while(i<512000) {
  myarr[i]=i;
  i++;
 };
}

Memory usage is 1016 KB, This is right...
:-(((((((((((((((((((((((((((((((((((((