# Find array elements with frequencies in range [l , r]

Given an array of integers, find the elements from the array whose frequency lies in the range [l, r].

Examples:

```Input : arr[] = { 1, 2, 3, 3, 2, 2, 5 }
l = 2, r = 3
Output : 2 3 3 2 2
```

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

Approach :

• Take a hash map, which will store the frequency of all the elements in the array.
• Now, traverse once again.
• Print the elements whose frequency lies between the range [l, r].

## C++

 `// C++ program to find the elements whose ` `// frequency lies in the range [l, r] ` `#include "iostream" ` `#include "unordered_map" ` `using` `namespace` `std; ` ` `  `void` `findElements(``int` `arr[], ``int` `n, ``int` `l, ``int` `r) ` `{ ` `    ``// Hash map which will store the ` `    ``// frequency of the elements of the array. ` `    ``unordered_map<``int``, ``int``> mp; ` ` `  `    ``for` `(``int` `i = 0; i < n; ++i) { ` ` `  `        ``// Increment the frequency ` `        ``// of the element by 1. ` `        ``mp[arr[i]]++; ` `    ``} ` ` `  `    ``for` `(``int` `i = 0; i < n; ++i) { ` ` `  `        ``// Print the element whose frequency ` `        ``// lies in the range [l, r] ` `        ``if` `(l <= mp[arr[i]] && mp[arr[i] <= r]) { ` `            ``cout << arr[i] << ``" "``; ` `        ``} ` `    ``} ` `} ` ` `  `int` `main() ` `{ ` `    ``int` `arr[] = { 1, 2, 3, 3, 2, 2, 5 }; ` `    ``int` `n = ``sizeof``(arr) / ``sizeof``(arr); ` `    ``int` `l = 2, r = 3; ` `    ``findElements(arr, n, l, r); ` `    ``return` `0; ` `} `

## Java

 `import` `java.util.HashMap; ` `import` `java.util.Map; ` ` `  `// Java program to find the elements whose ` `// frequency lies in the range [l, r] ` `public` `class` `GFG { ` ` `  `    ``static` `void` `findElements(``int` `arr[], ``int` `n, ``int` `l, ``int` `r) { ` `        ``// Hash map which will store the ` `        ``// frequency of the elements of the array. ` `        ``Map mp = ``new` `HashMap(); ` ` `  `        ``for` `(``int` `i = ``0``; i < n; ++i) { ` ` `  `            ``// Increment the frequency ` `            ``// of the element by 1. ` `            ``int` `a=``0``; ` `            ``if``(mp.get(arr[i])==``null``){ ` `                ``a=``1``; ` `            ``} ` `            ``else``{ ` `                ``a = mp.get(arr[i])+``1``; ` `            ``} ` `            ``mp.put(arr[i], a); ` `        ``} ` ` `  `        ``for` `(``int` `i = ``0``; i < n; ++i) { ` ` `  `            ``// Print the element whose frequency ` `            ``// lies in the range [l, r] ` `            ``if` `(l <= mp.get(arr[i]) && (mp.get(arr[i]) <= r)) { ` `                ``System.out.print(arr[i] + ``" "``); ` `            ``} ` `        ``} ` `    ``} ` ` `  `    ``public` `static` `void` `main(String[] args) { ` `        ``int` `arr[] = {``1``, ``2``, ``3``, ``3``, ``2``, ``2``, ``5``}; ` `        ``int` `n = arr.length; ` `        ``int` `l = ``2``, r = ``3``; ` `        ``findElements(arr, n, l, r); ` ` `  `    ``} ` `} ` `/*This code is contributed by PrinciRaj1992*/`

## Python3

 `# Python 3 program to find the elements whose ` `# frequency lies in the range [l, r] ` ` `  `def` `findElements(arr, n, l, r): ` `     `  `    ``# Hash map which will store the ` `    ``# frequency of the elements of the array. ` `    ``mp ``=` `{i:``0` `for` `i ``in` `range``(``len``(arr))} ` ` `  `    ``for` `i ``in` `range``(n): ` `         `  `        ``# Increment the frequency ` `        ``# of the element by 1. ` `        ``mp[arr[i]] ``+``=` `1` ` `  `    ``for` `i ``in` `range``(n): ` `         `  `        ``# Print the element whose frequency ` `        ``# lies in the range [l, r] ` `        ``if` `(l <``=` `mp[arr[i]] ``and` `mp[arr[i] <``=` `r]): ` `            ``print``(arr[i], end ``=` `" "``) ` `     `  `# Driver Code ` `if` `__name__ ``=``=` `'__main__'``: ` `    ``arr ``=` `[``1``, ``2``, ``3``, ``3``, ``2``, ``2``, ``5``] ` `    ``n ``=` `len``(arr) ` `    ``l ``=` `2` `    ``r ``=` `3` `    ``findElements(arr, n, l, r) ` `     `  `# This code is contributed by ` `# Shashank_Sharma `

## C#

 `// C# program to find the elements whose ` `// frequency lies in the range [l, r] ` `using` `System; ` `using` `System.Collections.Generic; ` ` `  `class` `GFG  ` `{ ` ` `  `    ``static` `void` `findElements(``int` `[]arr, ``int` `n, ``int` `l, ``int` `r) ` `    ``{ ` `        ``// Hash map which will store the ` `        ``// frequency of the elements of the array. ` `        ``Dictionary<``int``, ``int``> mp = ``new` `Dictionary<``int``, ``int``>(); ` ` `  `        ``for` `(``int` `i = 0; i < n; ++i)  ` `        ``{ ` ` `  `            ``// Increment the frequency ` `            ``// of the element by 1. ` `            ``int` `a = 0; ` `            ``if``(!mp.ContainsKey(arr[i])) ` `            ``{ ` `                ``a = 1; ` `            ``} ` `            ``else` `            ``{ ` `                ``a = mp[arr[i]]+1; ` `            ``} ` `             `  `            ``if``(!mp.ContainsKey(arr[i])) ` `            ``{ ` `                ``mp.Add(arr[i], a);  ` `            ``} ` `            ``else` `            ``{ ` `                ``mp.Remove(arr[i]); ` `                ``mp.Add(arr[i], a); ` `            ``} ` `        ``} ` ` `  `        ``for` `(``int` `i = 0; i < n; ++i) ` `        ``{ ` ` `  `            ``// Print the element whose frequency ` `            ``// lies in the range [l, r] ` `            ``if` `(mp.ContainsKey(arr[i]) &&  ` `                        ``l <= mp[arr[i]] && ` `                        ``(mp[arr[i]] <= r))  ` `            ``{ ` `                ``Console.Write(arr[i] + ``" "``); ` `            ``} ` `        ``} ` `    ``} ` `     `  `    ``// Driver code ` `    ``public` `static` `void` `Main(String[] args) ` `    ``{ ` `        ``int` `[]arr = {1, 2, 3, 3, 2, 2, 5}; ` `        ``int` `n = arr.Length; ` `        ``int` `l = 2, r = 3; ` `        ``findElements(arr, n, l, r); ` ` `  `    ``} ` `} ` ` `  `// This code has been contributed by 29AjayKumar `

Output:

```2 3 3 2 2
```

Time Complexity – O(N)

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.