# Count the elements having frequency equals to its value

Given an array of integers arr[] of size N, the task is to count all the elements of the array which have a frequency equals to its value.

Examples:

Input: arr[] = {3, 2, 2, 3, 4, 3}
Output: 2
Frequency of element 2 is 2
Frequency of element 3 is 3
Frequency of element 4 is 1
2 and 3 are elements which have same frequency as it’s value

Input: arr[] = {1, 2, 3, 4, 5, 6}
Output: 1

## Recommended: Please try your approach on {IDE} first, before moving on to the solution.

Approach: Store the frequency of every element of the array using the map, and finally count all of that elements whose frequency is equal to their value.

Below is the implementation of the above approach:

## C++

 `// C++ program to count the elements ` `// having frequency equals to its value ` ` `  `#include ` `using` `namespace` `std; ` ` `  `// Function to find the count ` `int` `find_maxm(``int` `arr[], ``int` `n) ` `{ ` `    ``// Hash map for counting frquency ` `    ``map<``int``, ``int``> mpp; ` ` `  `    ``for` `(``int` `i = 0; i < n; i++) { ` ` `  `        ``// Counting freq of each element ` `        ``mpp[arr[i]] += 1; ` `    ``} ` ` `  `    ``int` `ans = 0; ` `    ``for` `(``auto` `x : mpp) { ` `        ``int` `value = x.first; ` `        ``int` `freq = x.second; ` ` `  `        ``// Check if value equls to frequency ` `        ``// and increment the count ` `        ``if` `(value == freq) { ` `            ``ans++; ` `        ``} ` `    ``} ` ` `  `    ``return` `ans; ` `} ` ` `  `// Driver code ` `int` `main() ` `{ ` `    ``int` `arr[] = { 3, 2, 2, 3, 4, 3 }; ` `    ``int` `n = ``sizeof``(arr) / ``sizeof``(arr); ` ` `  `    ``// Function call ` `    ``cout << find_maxm(arr, n); ` ` `  `    ``return` `0; ` `} `

## Java

 `// Java program to count the elements ` `// having frequency equals to its value ` `import` `java.util.*; ` ` `  `class` `GFG{ ` `  `  `// Function to find the count ` `static` `int` `find_maxm(``int` `arr[], ``int` `n) ` `{ ` `    ``// Hash map for counting frquency ` `    ``HashMap mp = ``new` `HashMap(); ` `  `  `    ``for` `(``int` `i = ``0``; i < n; i++) { ` `  `  `        ``// Counting freq of each element ` `        ``if``(mp.containsKey(arr[i])){ ` `            ``mp.put(arr[i], mp.get(arr[i])+``1``); ` `        ``}``else``{ ` `            ``mp.put(arr[i], ``1``); ` `    ``} ` `    ``} ` `  `  `    ``int` `ans = ``0``; ` `    ``for` `(Map.Entry x : mp.entrySet()){ ` `        ``int` `value = x.getKey(); ` `        ``int` `freq = x.getValue(); ` `  `  `        ``// Check if value equls to frequency ` `        ``// and increment the count ` `        ``if` `(value == freq) { ` `            ``ans++; ` `        ``} ` `    ``} ` `  `  `    ``return` `ans; ` `} ` `  `  `// Driver code ` `public` `static` `void` `main(String[] args) ` `{ ` `    ``int` `arr[] = { ``3``, ``2``, ``2``, ``3``, ``4``, ``3` `}; ` `    ``int` `n = arr.length; ` `  `  `    ``// Function call ` `    ``System.out.print(find_maxm(arr, n));  ` `} ` `} ` ` `  `// This code is contributed by Princi Singh `

## C#

 `// C# program to count the elements ` `// having frequency equals to its value ` `using` `System; ` `using` `System.Collections.Generic; ` ` `  `class` `GFG{ ` `   `  `// Function to find the count ` `static` `int` `find_maxm(``int` `[]arr, ``int` `n) ` `{ ` `    ``// Hash map for counting frquency ` `    ``Dictionary<``int``,``int``> mp = ``new` `Dictionary<``int``,``int``>(); ` `   `  `    ``for` `(``int` `i = 0; i < n; i++) { ` `   `  `        ``// Counting freq of each element ` `        ``if``(mp.ContainsKey(arr[i])){ ` `            ``mp[arr[i]] = mp[arr[i]] + 1; ` `        ``}``else``{ ` `            ``mp.Add(arr[i], 1); ` `    ``} ` `    ``} ` `   `  `    ``int` `ans = 0; ` `    ``foreach` `(KeyValuePair<``int``,``int``> x ``in` `mp){ ` `        ``int` `value = x.Key; ` `        ``int` `freq = x.Value; ` `   `  `        ``// Check if value equls to frequency ` `        ``// and increment the count ` `        ``if` `(value == freq) { ` `            ``ans++; ` `        ``} ` `    ``} ` `   `  `    ``return` `ans; ` `} ` `   `  `// Driver code ` `public` `static` `void` `Main(String[] args) ` `{ ` `    ``int` `[]arr = { 3, 2, 2, 3, 4, 3 }; ` `    ``int` `n = arr.Length; ` `   `  `    ``// Function call ` `    ``Console.Write(find_maxm(arr, n));  ` `} ` `} ` ` `  `// This code is contributed by PrinciRaj1992 `

Output:

```2
```

Don’t stop now and take your learning to the next level. Learn all the important concepts of Data Structures and Algorithms with the help of the most trusted course: DSA Self Paced. Become industry ready at a student-friendly price.

My Personal Notes arrow_drop_up Check out this Author's contributed articles.

If you like GeeksforGeeks and would like to contribute, you can also write an article using contribute.geeksforgeeks.org or mail your article to contribute@geeksforgeeks.org. See your article appearing on the GeeksforGeeks main page and help other Geeks.

Please Improve this article if you find anything incorrect by clicking on the "Improve Article" button below.