JavaAlgorithms/Misc/MedianOfRunningArray.java

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Java
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2018-10-11 13:55:26 +08:00
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() + " ");
}
}
}