Maps STL HackerRank Problem

Maps-STLHackerRank.cpp

#include <cmath>
#include <cstdio>
#include <vector>
#include <iostream>
#include <set>
#include <map>
#include <algorithm>
#include<string>
using namespace std;


int main() {
    int q;
    cin>>q;
    map<string, int> m;
    map<string, int>::iterator itr;
    while(q){
        int val, marks;
        string name;
        cin>>val>>name;
        itr = m.find(name);
        switch(val){
            case 1: 
                cin>>marks;
                if(itr!=m.end()){
                    m[name] += marks;
                }else{
                    m.insert(make_pair(name, marks));
                }
                break;
            case 2:
                if(itr!=m.end()){
                    m.erase(name);
                }
                break;
            case 3:
                if(itr!=m.end()){
                    cout<<m[name]<<endl;
                }else{
                    cout<<"0"<<endl;
                }
                break;
        }
        q--;
    }
    return 0;
}