Finding MK Average

You are given two integers, `m` and `k`, and a stream of integers. You are tasked to implement a data structure that calculates the **MKAverage** for the stream. The **MKAverage** can be calculated using these steps: - If the number of the elements in the stream is less than `m` you should consider the **MKAverage** to be `-1`. Otherwise, copy the last `m` elements of the stream to a separate container. - Remove the smallest `k` elements and the largest `k` elements from the container. - Calculate the average value for the rest of the elements **rounded down to the nearest integer**. Implement the `MKAverage` class: - `MKAverage(int m, int k)` Initializes the **MKAverage** object with an empty stream and the two integers `m` and `k`. - `void addElement(int num)` Inserts a new element `num` into the stream. - `int calculateMKAverage()` Calculates and returns the **MKAverage** for the current stream **rounded down to the nearest integer**.   **Example 1:** **Input** ["MKAverage", "addElement", "addElement", "calculateMKAverage", "addElement", "calculateMKAverage", "addElement", "addElement", "addElement", "calculateMKAverage"] [[3, 1], [3], [1], [], [10], [], [5], [5], [5], []] **Output** [null, null, null, -1, null, 3, null, null, null, 5] **Explanation** `MKAverage obj = new MKAverage(3, 1); obj.addElement(3); // current elements are [3] obj.addElement(1); // current elements are [3,1] obj.calculateMKAverage(); // return -1, because m = 3 and only 2 elements exist. obj.addElement(10); // current elements are [3,1,10] obj.calculateMKAverage(); // The last 3 elements are [3,1,10]. // After removing smallest and largest 1 element the container will be [3]. // The average of [3] equals 3/1 = 3, return 3 obj.addElement(5); // current elements are [3,1,10,5] obj.addElement(5); // current elements are [3,1,10,5,5] obj.addElement(5); // current elements are [3,1,10,5,5,5] obj.calculateMKAverage(); // The last 3 elements are [5,5,5]. // After removing smallest and largest 1 element the container will be [5]. // The average of [5] equals 5/1 = 5, return 5 ` ```   **Constraints:** - `3 <= m <= 105` - `1 < k*2 < m` - `1 <= num <= 105` - At most `105` calls will be made to `addElement` and `calculateMKAverage`.