Inversion Count Problem

Given an integer array ARR of size N with all distinct values, determine the total number of 'Inversions' that exist.

Explanation:

An inversion is a pair of indices (i, j) such that:

• ARR[i] > ARR[j]
• i < j

Input:

N
ARR[0] ARR[1] ... ARR[N-1]

Output:

The total count of inversions in the array.

Example:

Input:

5
2 4 1 3 5

Output:

3

Explanation:

There are 3 inversions in the array: (2, 1), (4, 1), and (4, 3).

Constraints:

• 1 <= N <= 10^5
• 1 <= ARR[i] <= 10^9

Note:

You do not need to print anything; just implement the function that returns the count of inversions.