Solution of 'Maps-STL' (Hackerrank)

So, here's my solution of the question- Maps-STL of Hackerrank. If you guys have any suggestions, do comment. Thank you and Happy coding.

link: https://www.hackerrank.com/challenges/cpp-maps/problem

#include <cstdio>

 #include <cmath>

#include <vector>

#include <iostream>

#include <set>

#include <map>

#include <algorithm>

using namespace std;

int main()

{

    int q;

    cin>>q;

    int a[q];

    map<string,int> mark;

    for(int i=0;i<q;i++){

        cin>>a[i];

        if(a[i]==1){

            string p;

            int k;

            cin>>p>>k;

            mark[p]+=k;

        }

        else if(a[i]==2){

            string p;

            cin>>p;

            mark[p]=0;

        }

        else if(a[i]==3){

            string p;

            cin>>p;

            cout<<mark[p]<<'\n';

        }

    } 

}