Java/Misc/MedianOfRunningArray.java at master · primary-code-test/Java · GitHub

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package Misc;

import java.util.Collections;

import java.util.PriorityQueue;

/** @author shrutisheoran */

public class MedianOfRunningArray {

private PriorityQueue<Integer> p1;

private PriorityQueue<Integer> p2;

// Constructor

public MedianOfRunningArray() {

this.p1 = new PriorityQueue<>(Collections.reverseOrder()); // Max Heap

this.p2 = new PriorityQueue<>(); // Min Heap

}

Inserting lower half of array to max Heap

and upper half to min heap

public void insert(Integer e) {

p2.add(e);

if (p2.size() - p1.size() > 1) p1.add(p2.remove());

}

Returns median at any given point

public Integer median() {

if (p1.size() == p2.size()) return (p1.peek() + p2.peek()) / 2;

return p1.size() > p2.size() ? p1.peek() : p2.peek();

}

public static void main(String[] args) {

Testing the median function

MedianOfRunningArray p = new MedianOfRunningArray();

int arr[] = {10, 7, 4, 9, 2, 3, 11, 17, 14};

for (int i = 0; i < 9; i++) {

p.insert(arr[i]);

System.out.print(p.median() + " ");

}