Sets STL in C++ | HackerRank Solution

Hello there, today we are going to solve Sets STL Hacker Rank Solution in C++.

Table Of Contents 👊

• Objective
• Input Format
• Constraints
• Output Format
• Solution

Objective

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:

set<int>s; //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<int>::iterator itr=s.find(val); //Gives the iterator to the element val if it is found otherwise returns s.end() .
Ex: set<int>::iterator itr=s.find(100); //If 100 is not present then it==s.end().

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

Input Format

The first line of the input contains Q where Q is the number of queries. The next Q lines contain 1 query each. Each query consists of two integers y and x where y is the type of the query and x is an integer.

Constraints

• 1 <= Q <= 10^5
• 1 <= y <= 3
• 1 <= x <= 10^9

Output Format

For queries of type 3 print "Yes"(without quotes) if the number x is present in the set and if the number is not present, then print "No"(without quotes).

Each query of type 3 should be printed in a new line.

Sample Input 

8
1 9
1 6
1 10
1 4
3 6
3 14
2 6
3 6

Sample Output 

Yes
No
No

Solution - Sets STL in C++

#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;
}

Disclaimer: The above Problem (Sets STL) is generated by Hacker Rank but the Solution is Provided by Sloth Coders. This tutorial is only for Educational and Learning Purpose.