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# Sum of elements in an array with frequencies greater than or equal to that element

• Last Updated : 09 Jun, 2021

Given an array arr[] of N integers. The task is to find the sum of the elements which have frequencies greater than or equal to that element in the array.
Examples

```Input: arr[] = {2, 1, 1, 2, 1, 6}
Output: 3
The elements in the array are {2, 1, 6}
Where,
2 appear 2 times which is greater than equal to 2 itself.
1 appear 3 times which is greater than 1 itself.
But 6 appears 1 time which is not greater than or equals to 6.
So, sum = 2 + 1 = 3.

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

Approach:

• Traverse the array and store the frequencies of all the elements in an unordered_map in C++ or equivalent data structure in any other programming language.
• Calculate the sum of elements having frequencies greater than or equal to that element.

Below is the implementation of the above approach:

## C++

 `// C++ program to find sum of elements``// in an array having frequency greater``// than or equal to that element` `#include ``using` `namespace` `std;` `// Function to return the sum of elements``// in an array having frequency greater``// than or equal to that element``int` `sumOfElements(``int` `arr[], ``int` `n)``{``    ``bool` `prime[n + 1];``    ``int` `i, j;` `    ``// Map is used to store``    ``// element frequencies``    ``unordered_map<``int``, ``int``> m;``    ``for` `(i = 0; i < n; i++)``        ``m[arr[i]]++;` `    ``int` `sum = 0;` `    ``// Traverse the map using iterators``    ``for` `(``auto` `it = m.begin(); it != m.end(); it++) {` `        ``// Calculate the sum of elements``        ``// having frequencies greater than``        ``// or equal to the element itself``        ``if` `((it->second) >= (it->first)) {``            ``sum += (it->first);``        ``}``    ``}` `    ``return` `sum;``}` `// Driver code``int` `main()``{``    ``int` `arr[] = { 1, 2, 3, 3, 2, 3, 2, 3, 3 };``    ``int` `n = ``sizeof``(arr) / ``sizeof``(arr);` `    ``cout << sumOfElements(arr, n);` `    ``return` `0;``}`

## Java

 `// Java program to find sum of elements``// in an array having frequency greater``// than or equal to that element``import` `java.util.*;``class` `Solution``{` `// Function to return the sum of elements``// in an array having frequency greater``// than or equal to that element``static` `int` `sumOfElements(``int` `arr[], ``int` `n)``{``    ``boolean` `prime[] = ``new` `boolean``[n + ``1``];``    ``int` `i, j;` `    ``// Map is used to store``    ``// element frequencies``    ``HashMap m= ``new` `HashMap();``    ``for` `(i = ``0``; i < n; i++)``        ``{``            ``if``(m.get(arr[i])==``null``)``            ``m.put(arr[i],``1``);``            ``else``            ``m.put(arr[i],m.get(arr[i])+``1``);``        ``}` `    ``int` `sum = ``0``;``        ``// Getting an iterator``        ``Iterator hmIterator = m.entrySet().iterator();``  ` `  ` `    ``// Traverse the map using iterators``        ``while` `(hmIterator.hasNext()) {``            ``Map.Entry mapElement = (Map.Entry)hmIterator.next();` `        ``// Calculate the sum of elements``        ``// having frequencies greater than``        ``// or equal to the element itself``        ``if` `(((``int``)mapElement.getValue()) >= ((``int``)mapElement.getKey())) {``            ``sum += ((``int``)mapElement.getKey());``        ``}``    ``}` `    ``return` `sum;``}` `// Driver code``public` `static` `void` `main(String args[])``{``    ``int` `arr[] = { ``1``, ``2``, ``3``, ``3``, ``2``, ``3``, ``2``, ``3``, ``3` `};``    ``int` `n = arr.length;` `    ``System.out.println(sumOfElements(arr, n));` ` ``}``}``//contributed by Arnab Kundu`

## Python3

 `# Python3 program to find sum of elements``# in an array having frequency greater``# than or equal to that element` `# Function to return the sum of elements``# in an array having frequency greater``# than or equal to that element``def` `sumOfElements(arr, n) :` `    ``# dictionary is used to store``    ``# element frequencies``    ``m ``=` `dict``.fromkeys(arr, ``0``)` `    ``for` `i ``in` `range``(n) :``            ``m[arr[i]] ``+``=` `1` `    ``sum` `=` `0` `    ``# traverse the dictionary``    ``for` `key,value ``in` `m.items() :` `        ``# Calculate the sum of elements``        ``# having frequencies greater than``        ``# or equal to the element itself``        ``if` `value >``=` `key :``                ``sum` `+``=` `key` `    ``return` `sum` `# Driver code``if` `__name__ ``=``=` `"__main__"` `:` `    ``arr ``=` `[``1``, ``2``, ``3``, ``3``, ``2``, ``3``, ``2``, ``3``, ``3``]``    ``n ``=` `len``(arr)` `    ``print``(sumOfElements(arr, n))` `# This code is contributed by Ryuga`

## C#

 `// C# program to find sum of elements``// in an array having frequency greater``// than or equal to that element``using` `System;``using` `System.Collections.Generic;` `class` `GFG``{` `    ``// Function to return the sum of elements``    ``// in an array having frequency greater``    ``// than or equal to that element``    ``static` `int` `sumOfElements(``int` `[]arr, ``int` `n)``    ``{``        ``bool` `[]prime = ``new` `bool``[n + 1];``        ``int` `i;``    ` `        ``// Map is used to store``        ``// element frequencies``        ``Dictionary<``int``, ``int``> m= ``new` `Dictionary<``int``,``int``>();``        ``for` `(i = 0; i < n; i++)``            ``{``                ``if``(!m.ContainsKey(arr[i]))``                    ``m.Add(arr[i],1);``                ``else``                ``{``                    ``var` `val = m[arr[i]];``                    ``m.Remove(arr[i]);``                    ``m.Add(arr[i], val + 1);``                ``}``            ` `            ``}``    ` `            ``int` `sum = 0;``            ``// Calculate the sum of elements``            ``// having frequencies greater than``            ``// or equal to the element itself``            ``foreach``(KeyValuePair<``int``, ``int``> entry ``in` `m)``            ``{``                ``if``(entry.Value >= entry.Key)``                ``{``                    ``sum+=entry.Key;``                ``}``            ``}``    ` `        ``return` `sum;``    ``}``    ` `    ``// Driver code``    ``public` `static` `void` `Main(String []args)``    ``{``        ``int` `[]arr = { 1, 2, 3, 3, 2, 3, 2, 3, 3 };``        ``int` `n = arr.Length;``    ` `        ``Console.WriteLine(sumOfElements(arr, n));``    ``}``}` `// This code has been contributed by 29AjayKumar`

## Javascript

 ``
Output
`6`

Time complexity: O(n)

#### Approach:

• Calculate the frequencies using Counter() function
• Calculate the sum of elements having frequencies greater than or equal to that element.

## Python3

 `# Python program for the above approach``from` `collections ``import` `Counter` `# Function to return the sum of elements``# in an array having frequency greater``# than or equal to that element``def` `sumOfElements(arr, n):` `    ``# Counter function is used to``    ``# calculate frequency of elements of array``    ``m ``=` `Counter(arr)` `    ``sum` `=` `0` `    ``# traverse the dictionary``    ``for` `key, value ``in` `m.items():` `        ``# Calculate the sum of elements``        ``# having frequencies greater than``        ``# or equal to the element itself``        ``if` `value >``=` `key:``            ``sum` `+``=` `key` `    ``return` `sum`  `# Driver code``if` `__name__ ``=``=` `"__main__"``:` `    ``arr ``=` `[``1``, ``2``, ``3``, ``3``, ``2``, ``3``, ``2``, ``3``, ``3``]``    ``n ``=` `len``(arr)` `    ``print``(sumOfElements(arr, n))` `# This code is contributed by vikkycirus`
Output
`6`

Time Complexity: O(n)

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