You are managing a warehouse inventory system. Due to a sudden change in shipping priority, you need to reverse the order of items in a list. Write a function `reverseArray(vector<int>& arr)` that reverses the given array of integers **in-place** (without allocating extra space for another array). ### Input Format - A vector of integers `arr`. ### Output Format - The function should modify `arr` in-place. ### Constraints - `1 <= arr.size() <= 10^5` - `-10^9 <= arr[i] <= 10^9`
Explanation: Reversing [1, 2, 3, 4, 5] gives [5, 4, 3, 2, 1].
Explanation: Reversing [10, 20] gives [20, 10].