I use: vector<int> v[1000];
Empty programm "eates" 100kb of memory.
Vector has special mem allocation (allocates everytime then needed only space for 15 elements).
So maxinun there are only 15000 unseed elements.
So (100000+15000)*4=460000bytes = 450kb + 100 = 550kb
So there are 200kb for programm stack. Is it not enogh?
However i got TLE.
Any suggestions?

Memory allocation will work very slow of course
Try to solve it with simple array without vector

UPS... i got not TLE, but MLE..
If I allocate each element, then got TLE... So I desided to use allocate each 12 elemtents, but got MLE...

I think when we use container with each anelement
we store pointer and memory size dublicated

I think that dynamic memory manager can't
pack data closely and free space appears

Once again! WHY MLE?

struct Value
{
    unsigned char value[4];
    unsigned char prev[3];
};

Value data[100000];
int top[1001];
int size;

int main ()
{
    assert(sizeof(Value) == 7);
....

It is possible to save only some more (2 or 3) bits. But data alinging will eat them.

Also another question:
struct stA
{
    int value;
    unsigned char prev[3];
};

struct stB
{
    int value;
    int prev : 18;
};

struct stC
{
    unsigned char value[4];
    unsigned char prev[3];
};

(sizeof(stA) == sizeof(stB) == 8) != (sizeof(stC) == 7)
Why?

//#include<fstream>;
#include<iostream>;
#include<string>
using namespace std;
//ofstream cout("out.txt");
//ifstream cin("in.txt");
string ch;

struct telem
{
int val;
telem *nx;
};
int n,a,b,i;
telem *st[1001],*k;

int main()
{
cin>>n;
for(i=0;i<n;i++)
  {
  cin>>ch;


  if (ch=="PUSH")
    {
    cin>>b>>a;
    k=st[b];
    st[b]=new telem;
    st[b]->val=a;
    st[b]->nx=k;
    }
  if (ch=="POP")
   {
    cin>>b;
    cout<<st[b]->val<<endl;
    k=st[b]->nx;
    delete(st[b]);
    st[b]=k;
    }
  }
return 0 ;}