HackerRank C++ Sets-STL

Sets are a part of the C++ STL. Sets are containers that store unique elements following a specific order. Here are some of the frequently used member functions of sets:

Declaration:

sets; //Creates a set of integers.
Size:

int length=s.size(); //Gives the size of the set.
Insert:

s.insert(x); //Inserts an integer x into the set s.
Erasing an element:

s.erase(val); //Erases an integer val from the set s.
Finding an element:

set::iterator itr=s.find(val); //Gives the iterator to the element val if it is found otherwise returns s.end() .
Ex: set::iterator itr=s.find(100); //If 100 is not present then it==s.end().
Coming to the problem, you will be given Q queries. Each query is of one of the following three types:

: Add an element x to the set.
: Delete an element x from the set. (If the number is not present in the set, then do nothing).
: If the number x is present in the set, then print "Yes"(without quotes) else print "No"(without quotes).

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


int main() 
{
    /* Enter your code here. Read input from STDIN. Print output to STDOUT */

    int n;
    set<int>s;
    for(int i=0;i<n;i++)
        {
        int a;
        cin>>a;
        s.insert(a);
        }
    cin>>n;
    for(int i=0;i<n;i++)
        {
        int q,t;
        cin>>t>>q;
        switch(t)
            {
            case 1:
            {
                s.insert(q);
                break;
            }
            case 2:
            {
                s.erase(q);
                break;
            }
            case 3:
            {
                set<int>::iterator itr=s.find(q);
                if(itr==s.end())
                   cout<<"No"<<endl;
                else
                   cout<<"Yes"<<endl;
                break;
            }
            }
        }
    return 0;
}