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Commit 5fee204

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Added PriorityQueueSort algorithm and Tests (#6532)
* Added PriorityQueueSort.java Implemented PriorityQueueSort using Java's PriorityQueue (Min-Heap). - Returns the array sorted in ascending order - Time complexity: O(n log n) - Space complexity: O(n) * Added tests for PriorityQueueSort * Update PriorityQueueSortTest.java * Fixed formatting and added full coverage tests for PriorityQueueSort * Update PriorityQueueSort.java * Update PriorityQueueSort.java * Update PriorityQueueSort.java * Update PriorityQueueSortTest.java * Update PriorityQueueSort.java * Update PriorityQueueSort.java * Update PriorityQueueSort.java * Fix formatting with clang-format
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package com.thealgorithms.sorts;
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import java.util.PriorityQueue;
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/**
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* Sorts an array using Java's PriorityQueue (Min-Heap).
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*
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* <p>Example: Input: [7, 2, 9, 4, 1] Output: [1, 2, 4, 7, 9]
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*
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* <p>Time Complexity:
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* - Inserting n elements into the PriorityQueue → O(n log n)
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* - Polling n elements → O(n log n)
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* - Total: O(n log n)
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*
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* <p>Space Complexity: O(n) for the PriorityQueue
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*
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* @see <a href="https://en.wikipedia.org/wiki/Heap_(data_structure)">
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* Heap / PriorityQueue</a>
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*/
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public final class PriorityQueueSort {
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// Private constructor to prevent instantiation (utility class)
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private PriorityQueueSort() {
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}
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/**
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* Sorts the given array in ascending order using a PriorityQueue.
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*
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* @param arr the array to be sorted
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* @return the sorted array (in-place)
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*/
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public static int[] sort(int[] arr) {
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if (arr == null || arr.length == 0) {
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return arr;
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}
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PriorityQueue<Integer> pq = new PriorityQueue<>();
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for (int num : arr) {
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pq.offer(num);
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}
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int i = 0;
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while (!pq.isEmpty()) {
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arr[i++] = pq.poll();
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}
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return arr;
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}
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}
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package com.thealgorithms.sorts;
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import static org.junit.jupiter.api.Assertions.assertArrayEquals;
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import org.junit.jupiter.api.Test;
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class PriorityQueueSortTest {
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@Test
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void testNullArray() {
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int[] input = null;
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assertArrayEquals(null, PriorityQueueSort.sort(input));
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}
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@Test
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void testSingleElementArray() {
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int[] input = {5};
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int[] expected = {5};
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assertArrayEquals(expected, PriorityQueueSort.sort(input));
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}
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@Test
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void testSortNormalArray() {
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int[] input = {7, 2, 9, 4, 1};
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int[] expected = {1, 2, 4, 7, 9};
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assertArrayEquals(expected, PriorityQueueSort.sort(input));
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}
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@Test
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void testEmptyArray() {
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int[] input = {};
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int[] expected = {};
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assertArrayEquals(expected, PriorityQueueSort.sort(input));
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}
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@Test
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void testNegativeNumbers() {
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int[] input = {3, -1, 2, -5, 0};
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int[] expected = {-5, -1, 0, 2, 3};
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assertArrayEquals(expected, PriorityQueueSort.sort(input));
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}
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@Test
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void testAlreadySortedArray() {
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int[] input = {1, 2, 3, 4, 5};
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int[] expected = {1, 2, 3, 4, 5};
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assertArrayEquals(expected, PriorityQueueSort.sort(input));
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}
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@Test
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void testArrayWithDuplicates() {
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int[] input = {5, 1, 3, 3, 2, 5};
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int[] expected = {1, 2, 3, 3, 5, 5};
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assertArrayEquals(expected, PriorityQueueSort.sort(input));
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}
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}

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