Maximum element in an array which is equal to its frequency

Given an array of integers arr[] of size N, the task is to find the maximum element in the array whose frequecny equals to it’s value

Examples:

Input: arr[] = {3, 2, 2, 3, 4, 3}
Output: 3
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 and 3 is the maximum.

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 find out the maximum of those element whose frequency is equal to their value.

Below is the implementation of the above approach:

CPP

// C++ program to find the maximum element  
// whose frequency equals to it’s value 
  
#include <bits/stdc++.h> 
using namespace std; 
  
// Function to find the maximum element  
// whose frequency equals to it’s value 
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 it is the maximum element or not 
        if (value == freq) { 
            ans = max(ans, value); 
        } 
    } 
  
    return ans; 
} 
  
// Driver code 
int main() 
{ 
    int arr[] = { 3, 2, 2, 3, 4, 3 }; 
      
    // Size of array 
    int n = sizeof(arr) / sizeof(arr[0]); 
      
    // Function call 
    cout << find_maxm(arr, n); 
  
    return 0; 
} 

Java

// Java program to find the maximum element  
// whose frequency equals to it’s value 
import java.util.*; 
  
class GFG{ 
   
// Function to find the maximum element  
// whose frequency equals to it’s value 
static int find_maxm(int arr[], int n) 
{ 
    // Hash map for counting frquency 
    HashMap<Integer,Integer> mp = new HashMap<Integer,Integer>(); 
   
    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<Integer,Integer> x : mp.entrySet()) 
    { 
        int value = x.getKey(); 
        int freq = x.getValue(); 
           
        // Check if value equls to frequency 
        // and it is the maximum element or not 
        if (value == freq) { 
            ans = Math.max(ans, value); 
        } 
    } 
   
    return ans; 
} 
   
// Driver code 
public static void main(String[] args) 
{ 
    int arr[] = { 3, 2, 2, 3, 4, 3 }; 
       
    // Size of array 
    int n = arr.length; 
       
    // Function call 
    System.out.print(find_maxm(arr, n)); 
   
} 
} 
  
// This code is contributed by 29AjayKumar 

Python3

# Python3 program to find the maximum element  
# whose frequency equals to it’s value  
  
# Function to find the maximum element  
# whose frequency equals to it’s value  
def find_maxm(arr, n) : 
  
    # Hash map for counting frquency  
    mpp = {} 
  
    for i in range(0,n): 
        # Counting freq of each element  
        if(arr[i] in mpp): 
            mpp.update( {arr[i] : mpp[arr[i]] + 1} ) 
        else: 
            mpp[arr[i]] = 1
  
    ans = 0
    for value,freq in mpp.items(): 
        # Check if value equls to frequency  
        # and it is the maximum element or not  
        if (value == freq): 
            ans = max(ans, value) 
  
    return ans 
  
# Driver code  
arr = [ 3, 2, 2, 3, 4, 3 ] 
      
# Size of array  
n = len(arr) 
  
# Function call  
print(find_maxm(arr, n)) 
  
# This code is contributed by Sanjit_Prasad 

C#

// C# program to find the maximum element  
// whose frequency equals to it’s value 
using System; 
using System.Collections.Generic; 
  
class GFG{ 
    
// Function to find the maximum element  
// whose frequency equals to it’s value 
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 it is the maximum element or not 
        if (value == freq) { 
            ans = Math.Max(ans, value); 
        } 
    } 
    
    return ans; 
} 
    
// Driver code 
public static void Main(String[] args) 
{ 
    int []arr = { 3, 2, 2, 3, 4, 3 }; 
        
    // Size of array 
    int n = arr.Length; 
        
    // Function call 
    Console.Write(find_maxm(arr, n)); 
} 
} 
  
// This code is contributed by Rajput-Ji 

Output:

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

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

CPP

Java

Python3

C#

Recommended Posts: