Make Unique Array Challenge

Your task is to determine the minimum number of elements that need to be removed from an array 'ARR' of size 'N' such that all the remaining elements are distinct. In simpler terms, there should be no two indices 'I' and 'J' with 'I' ≠ 'J' and 'ARR'['I'] = 'ARR'['J'].

Example:

Input:

N = 4
ARR = [1, 2, 1, 2]

Output:

2

Explanation:

Since the numbers 1 and 2 are repeated, we need to remove 2 elements to make all numbers unique.

Constraints:

• 1 <= T <= 10
• 1 <= N <= 5000
• 0 <= ARR[i] <= 10^6
• Time Limit: 1 sec