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#4382 Bug Fix #4384

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Merged
merged 14 commits into from
Sep 21, 2023
Merged

#4382 Bug Fix #4384

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3b0ce38
#4382 Bug Fix
govardhanshah456 Sep 20, 2023
6ed1189
#4382 Bug Fix
govardhanshah456 Sep 20, 2023
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Made Requested Changes
govardhanshah456 Sep 20, 2023
0b7d2a3
Update src/main/java/com/thealgorithms/misc/MedianOfRunningArray.java
govardhanshah456 Sep 21, 2023
81e0d3d
Update src/main/java/com/thealgorithms/misc/MedianOfRunningArray.java
govardhanshah456 Sep 21, 2023
6c4c057
Update src/test/java/com/thealgorithms/misc/MedianOfRunningArrayTest.…
govardhanshah456 Sep 21, 2023
300b1eb
Update src/test/java/com/thealgorithms/misc/MedianOfRunningArrayTest.…
govardhanshah456 Sep 21, 2023
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Merge branch 'master' into MedianOfRunningArray-Bug-Fix
vil02 Sep 21, 2023
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42 changes: 20 additions & 22 deletions src/main/java/com/thealgorithms/misc/MedianOfRunningArray.java
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Original file line number Diff line number Diff line change
Expand Up @@ -8,46 +8,44 @@
*/
public class MedianOfRunningArray {

private PriorityQueue<Integer> p1;
private PriorityQueue<Integer> p2;
private PriorityQueue<Integer> maxHeap;
private PriorityQueue<Integer> minHeap;

// Constructor
public MedianOfRunningArray() {
this.p1 = new PriorityQueue<>(Collections.reverseOrder()); // Max Heap
this.p2 = new PriorityQueue<>(); // Min Heap
this.maxHeap = new PriorityQueue<>(Collections.reverseOrder()); // Max Heap
this.minHeap = 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());
if (!minHeap.isEmpty() && e < minHeap.peek()) {
maxHeap.offer(e);
if (maxHeap.size() > minHeap.size() + 1) {
minHeap.offer(maxHeap.poll());
}
} else {
minHeap.offer(e);
if (minHeap.size() > maxHeap.size() + 1) {
maxHeap.offer(minHeap.poll());
}
}
}

/*
Returns median at any given point
*/
public Integer median() {
if (p1.size() == p2.size()) {
return (p1.peek() + p2.peek()) / 2;
public double median() {
if (maxHeap.isEmpty() && minHeap.isEmpty()) {
throw new IllegalArgumentException("Enter at least 1 element, Median of empty list is not defined!");
}
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() + " ");
if (maxHeap.size() == minHeap.size()) {
return (maxHeap.peek() + minHeap.peek()) / 2.0;
}
return maxHeap.size() > minHeap.size() ? maxHeap.peek() * 1.0 : minHeap.peek() * 1.0;
}
}
161 changes: 161 additions & 0 deletions src/test/java/com/thealgorithms/misc/MedianOfRunningArrayTest.java
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Original file line number Diff line number Diff line change
@@ -0,0 +1,161 @@
package com.thealgorithms.misc;

import static org.junit.jupiter.api.Assertions.assertEquals;
import static org.junit.jupiter.api.Assertions.assertFalse;
import static org.junit.jupiter.api.Assertions.assertThrows;

import org.apache.commons.lang3.tuple.Pair;
import org.junit.jupiter.api.Test;

/**
* Test case for Two sum Problem.
* @author Bama Charan Chhandogi (https://github.com/BamaCharanChhandogi)
*/

public class MedianOfRunningArrayTest {
private static final String EXCEPTION_MESSAGE = "Enter at least 1 element, Median of empty list is not defined!";

@Test
public void testWhenInvalidInoutProvidedShouldThrowException() {
MedianOfRunningArray stream = new MedianOfRunningArray();
IllegalArgumentException exception = assertThrows(IllegalArgumentException.class, () -> stream.median());
assertEquals(exception.getMessage(), EXCEPTION_MESSAGE);
}

@Test
public void testWithNegativeValues() {
MedianOfRunningArray stream = new MedianOfRunningArray();
stream.insert(-1);
assertEquals(-1, stream.median());
stream.insert(-2);
assertEquals(-1.5, stream.median());
stream.insert(-3);
assertEquals(-2, stream.median());
}

@Test
public void testWithSingleValues() {
MedianOfRunningArray stream = new MedianOfRunningArray();
stream.insert(-1);
assertEquals(-1, stream.median());
}

@Test
public void testWithRandomValues() {
MedianOfRunningArray stream = new MedianOfRunningArray();
stream.insert(10);
assertEquals(10.0, stream.median());

stream.insert(5);
assertEquals(7.5, stream.median());

stream.insert(20);
assertEquals(10.0, stream.median());

stream.insert(15);
assertEquals(12.5, stream.median());

stream.insert(25);
assertEquals(15.0, stream.median());

stream.insert(30);
assertEquals(17.5, stream.median());

stream.insert(35);
assertEquals(20.0, stream.median());

stream.insert(1);
assertEquals(17.5, stream.median());
}

@Test
public void testWithNegativeAndPositiveValues() {
MedianOfRunningArray stream = new MedianOfRunningArray();
stream.insert(-1);
assertEquals(-1, stream.median());
stream.insert(2);
assertEquals(0.5, stream.median());
stream.insert(-3);
assertEquals(-1, stream.median());
}

@Test
public void testWithDuplicateValues() {
MedianOfRunningArray stream = new MedianOfRunningArray();
stream.insert(-1);
assertEquals(-1, stream.median());
stream.insert(-1);
assertEquals(-1, stream.median());
stream.insert(-1);
assertEquals(-1, stream.median());
}

@Test
public void testWithDuplicateValuesB() {
MedianOfRunningArray stream = new MedianOfRunningArray();
stream.insert(10);
stream.insert(20);
stream.insert(10);
stream.insert(10);
stream.insert(20);
stream.insert(0);
stream.insert(50);
assertEquals(10, stream.median());
}

@Test
public void testWithLargeValues() {
MedianOfRunningArray stream = new MedianOfRunningArray();
stream.insert(1000000);
assertEquals(1000000, stream.median());
stream.insert(12000);
assertEquals(506000, stream.median());
stream.insert(15000000);
assertEquals(1000000, stream.median());
stream.insert(2300000);
assertEquals(1650000.00, stream.median());
}

@Test
public void testWithLargeCountOfValues() {
MedianOfRunningArray stream = new MedianOfRunningArray();
for (int i = 1; i <= 1000; i++) stream.insert(i);
assertEquals(500.5, stream.median());
}

@Test
public void testWithThreeValuesInDescendingOrder() {
MedianOfRunningArray stream = new MedianOfRunningArray();
stream.insert(30);
stream.insert(20);
stream.insert(10);
assertEquals(20.0, stream.median());
}

@Test
public void testWithThreeValuesInOrder() {
MedianOfRunningArray stream = new MedianOfRunningArray();
stream.insert(10);
stream.insert(20);
stream.insert(30);
assertEquals(20.0, stream.median());
}

@Test
public void testWithThreeValuesNotInOrderA() {
MedianOfRunningArray stream = new MedianOfRunningArray();
stream.insert(30);
stream.insert(10);
stream.insert(20);
assertEquals(20.0, stream.median());
}

@Test
public void testWithThreeValuesNotInOrderB() {
MedianOfRunningArray stream = new MedianOfRunningArray();
stream.insert(20);
stream.insert(10);
stream.insert(30);
assertEquals(20.0, stream.median());
}
}