How to Create a Set of Pairs in C++?

In C++, sets are associative containers that store unique elements. On the other hand, pairs allow the users to store two data of different or the same type into a single object. In this article, we will learn how we can create a set of pairs in C++.

Example

Input: 
p1={1, 2} p2 ={3, 4}

Output:  
Elements of set:
Pair 1: (1, 2)
Pair 2: (3, 4)

Create a Set of Pairs in C++

To create a set of pairs in C++, we can simply use the following syntax:

 set<pair<dataType, dataType>>

This will declare a set where each element is a pair. We can then insert the pairs into the set using the std::set::insert() method.

C++ Program to Create a Set of Pairs

C++

// C++ program to create a set of pairs using pair
#include <iostream>
#include <set>
#include <utility>
using namespace std;
// Driver Code
int main()
{
    // Initialize a set of set of pairs
    set<pair<int, int> > s;

    // Insert pairs into the set
    s.insert({ 10, 20 });
    s.insert({ 30, 40 });
    s.insert({ 50, 60 });
    s.insert({ 70, 80 });
    // Duplicate pair, won't be inserted as set stores
    // unique elements only
    s.insert({ 30, 40 });

    int i = 1;

    // Print the pairs present in the set
    cout << "Elements of Set:" << endl;
    for (auto pair : s) {
        cout << "Pair " << i++ << ": ";
        cout << "(" << pair.first << ", " << pair.second
             << ")" << endl;
    }

    return 0;
}

Output

Elements of Set:
Pair 1: (10, 20)
Pair 2: (30, 40)
Pair 3: (50, 60)
Pair 4: (70, 80)

Time Complexity: O(N) where N is the number of pairs in the set.
Auxiliary Space: O(N)