makeElementsEqual.cpp

// CPP program to find the minimum number of 
// operations required to make all elements 
// of array equal 
#include <bits/stdc++.h> 
using namespace std; 

// function for min operation 
int minOperation (int arr[], int n) { 
    // Insert all elements in hash. 
    unordered_map<int, int> hash; 
    for (int i=0; i<n; i++) 
        hash[arr[i]]++; 

    // find the max frequency 
    int max_count = 0; 
    for (auto i : hash) 
        if (max_count < i.second) 
            max_count = i.second; 

    // return result 
    return (n - max_count); 
} 

// driver program 
int main() { 
    
    int arr[] = {1, 5, 2, 1, 3, 2, 1}; 
    int n = sizeof(arr) / sizeof(arr[0]); 
    cout << minOperation(arr, n); 
    return 0; 
}