C#: Count the frequency of an element in an array

Difficulty Level: EASY

Problem Statement:

You are given an array, which can contain duplicates, and print all the elements and their frequencies.

Input:

arr [] = {3,5,9,3,3,5,9,3,9,5}

Output:

3 occurs 4 times

5 occurs 3 times

9 occurs 3 times