Algorithm

Take a unordered_map / HashMap of pair.
Use a for loop to iterate the array.
If the element is not present in the map then insert it with frequency 1, otherwise increase the existing frequency by 1.
After visiting the whole array, we will find the element with the highest frequency and the element with the lowest frequency by iterating the map.

Code

#include <bits/stdc++.h>
using namespace std;

// Class to count frequencies using unordered_map (hash table)
class FrequencyCounter {
public:
    void Frequency(int arr[], int n)
    {
        unordered_map<int, int> map; // Stores frequency of each element

        // Count frequencies of all elements
        for (int i = 0; i < n; i++)
            map[arr[i]]++;

        int maxFreq = 0, minFreq = n;
        int maxEle = 0, minEle = 0;

        // Traverse the map to find elements with max and min frequencies
        for (auto it : map) {
            int element = it.first;
            int count = it.second;

            // Updat