CP/Two-Stack_in_an_array.cpp at main · harsha094/CP · GitHub

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// { Driver Code Starts
#include<bits/stdc++.h>

using namespace std;

class twoStacks
{
    int *arr;
    int size;
    int top1, top2;
public:
   twoStacks(int n=100){size = n; arr = new int[n]; top1 = -1; top2 = size;}

   void push1(int x);
   void push2(int x);
   int pop1();
   int pop2();
};


int main()
{

    int T;
    cin>>T;
    while(T--)
    {
        twoStacks *sq = new twoStacks();

        int Q;
        cin>>Q;
        while(Q--){
        int stack_no;
        cin>>stack_no;
        int QueryType=0;
        cin>>QueryType;

        if(QueryType==1)
        {
            int a;
            cin>>a;
            if(stack_no ==1)
            sq->push1(a);
            else if(stack_no==2)
            sq->push2(a);
        }else if(QueryType==2){
        	if(stack_no==1)
            cout<<sq->pop1()<<" ";
            else if(stack_no==2)
            cout<<sq->pop2()<<" ";

        }
        }
        cout<<endl;
    }
}
// } Driver Code Ends


//Function to push an integer into the stack1.
void twoStacks :: push1(int x)
{
    if(top2-top1>1){
        top1++;
        arr[top1]=x;
    }
}

//Function to push an integer into the stack2.
void twoStacks ::push2(int x)
{
    if(top2-top1>1){
        top2--;
        arr[top2]=x;
    }
}

//Function to remove an element from top of the stack1.
int twoStacks ::pop1()
{
    if(top1>=0){
        int ans = arr[top1];
        top1--;
        return ans;
    }
    else{
        return -1;
    }
}

//Function to remove an element from top of the stack2.
int twoStacks :: pop2()
{
    if(top2<size){
        int ans = arr[top2];
        top2++;
        return ans;
    }
    else{
        return -1;
    }
}