attending workshops hackerrank

#include<bits/stdc++.h>

using namespace std;

//Define the structs Workshops and Available_Workshops.
//Implement the functions initialize and CalculateMaxWorkshops
struct Workshops{
    int start_time,duration,end_time;
};

struct Available_Workshops{
    int n;
    Workshops* ptr;

};

Available_Workshops* initialize (int start_time[], int duration[], int n){
    Available_Workshops* aw=new Available_Workshops[1];
        aw->ptr=new Workshops[n]{};
        aw->n=n;
        for(int i=0;i<n;i++){
            aw->ptr[i].start_time=start_time[i];
            aw->ptr[i].duration=duration[i];
            aw->ptr[i].end_time=start_time[i]+duration[i];
        }
        return aw;
    }

bool overlap(const Workshops& a, const Workshops& b){
    if(b.start_time>=a.start_time && b.start_time<a.end_time){
        return true;
    }
    else if(a.start_time>=b.start_time && a.start_time<b.end_time){
        return true;
    }
    return 0;
}
int cmp(const void* a, const void* b){
    Workshops* aa=(Workshops*)a;
    Workshops* bb=(Workshops*)b;
    if(overlap(*aa, *bb)){
        return aa->end_time-bb->end_time;
    }
    return aa->start_time-bb->start_time;

}

int CalculateMaxWorkshops(Available_Workshops* ptr){

   qsort(ptr->ptr,ptr->n,sizeof(Workshops),cmp);

  // int s=0;
   int e=0;
   int c=0;
   for(int i=0;i<ptr->n;i++){
      if(!i){
          e=ptr->ptr[i].end_time;
          c++;
      }
      else if(ptr->ptr[i].start_time>=e){
          e=ptr->ptr[i].end_time;
          c++;
      }
   }


    return c;
}

//locked below this point

int main(int argc, char *argv[]) {
    int n; // number of workshops
    cin >> n;
    // create arrays of unknown size n
    int* start_time = new int[n];
    int* duration = new int[n];

    for(int i=0; i < n; i++){
        cin >> start_time[i];
    }
    for(int i = 0; i < n; i++){
        cin >> duration[i];
    }

    Available_Workshops * ptr;
    ptr = initialize(start_time,duration, n);
    cout << CalculateMaxWorkshops(ptr) << endl;
    return 0;
}