Package g1801_1900.s1825_finding_mk_average

Class MKAverage

  • public class MKAverage
extends Object
    1825 - Finding MK Average.

    Hard

    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:

    1. 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.
    2. Remove the smallest k elements and the largest k elements from the container.
    3. 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.

    • Constructor Detail

      • MKAverage

        public MKAverage​(int m,
                 int k)

    • Method Detail

      • addElement

        public void addElement​(int num)

      • calculateMKAverage

        public int calculateMKAverage()