TwoStack.c++

#include <iostream>
using namespace std;

class TwoStack
{
    public:
    int *arr;
    int size;
    int top1;
    int top2;

    TwoStack(int s)
    {
        this -> size = s;
        arr = new int[size];
        top1 = -1;
        top2 = s;
    }

    void push1(int num)
    {
        if(top2 - top1 > 1)
        {
            top1++;
            arr[top1] = num;
        }
    }

    void push2(int num)
    {
        if(top2 - top1 > 1)
        {
            top2--;
            arr[top2] = num;
        }
    }

    int pop1()
    {
        if(top1 >= 0)
        {
            int ans = arr[top1];
            top1--;
            return ans;
        }
        else
        {
            return -1;
        }
    }

    int pop2()
    {
        if(top2 < size)
        {
            int ans = arr[top2];
            top2++;
            return ans;
        }
        else
        {
            return -1;
        }
    }
};

int main()
{

    return 0;
}