Count pairs whose products exist in array - GeeksforGeeks

Count pairs whose products exist in array - GeeksforGeeks
Given an array, count those pair whose product value is present in array.

int countPairs(int arr[] , int n)

{

    int result = 0;

 

    // Create an empty hash-set that store all array element

    set< int > Hash;

 

    // Insert all array element into set

    for (int i = 0 ; i < n; i++)

        Hash.insert(arr[i]);

 

    // Generate all pairs and check is exist in 'Hash' or not

    for (int i = 0 ; i < n; i++)

    {

        for (int j = i + 1; j<n ; j++)

        {

            int product = arr[i]*arr[j];

 

            // if product exists in set then we increment

            // count by 1

            if (Hash.find(product) != Hash.end())

                result++;

        }

    }

 

    // return count of pairs whose product exist in array

    return result;

}

Read full article from Count pairs whose products exist in array - GeeksforGeeks