Welcome to the daily solving of our PROBLEM OF THE DAY with Karan Mashru. We will discuss the entire problem step-by-step and work towards developing an optimized solution. This will not only help you brush up on your concepts of Array but will also help you build up problem-solving skills.

In this problem, we are given, an array arr[] of N positive integers which can contain integers from 1 to P where elements can be repeated or can be absent from the array. Your task is to count the frequency of all numbers from 1 to N. Make in-place changes in arr[], such that arr[i] = frequency(i). Assume 1-based indexing.
Note: The elements greater than N in the array can be ignored for counting and modifying the array in place.

Example :

Input:
N = 5
arr[] = {2, 3, 2, 3, 5}
P = 5
Output:
0 2 2 0 1

Explanation: 
Counting frequencies of each array element
We have:
1 occurring 0 times.
2 occurring 2 times.
3 occurring 2 times.
4 occurring 0 times.
5 occurring 1 time.

Give the problem a try before going through the video. All the best!!!
Problem Link: https://practice.geeksforgeeks.org/problems/frequency-of-array-elements-1587115620/1
Solution IDE Link: https://ide.geeksforgeeks.org/online-cpp-compiler/fd742a66-fb6f-433f-ab7e-802c40161763