2025 init

exercises/heap.md

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+# Testing the heap property
+
+A [*binary heap*](https://en.wikipedia.org/wiki/Binary_heap) is a data structure that contains comparable objects and it is able to efficiently return the lowest element.
+This data structure relies on a binary tree to keep the insertion and deletion operations efficient. It is the base of the [*Heapsort* algorithm](https://en.wikipedia.org/wiki/Heapsort).
+
+Implement a `BinaryHeap` class with the following interface:
+
+```java
+class BinaryHeap<T> {
+
+    public BinaryHeap(Comparator<T> comparator) { ... }
+
+    public T pop() { ... }
+
+    public T peek() { ... }
+
+    public void push(T element) { ... }
+
+    public int count() { ... }
+
+}
+```
+
+A `BinaryHeap` instance is created using a `Comparator` object that represents the ordering criterion between the objects in the heap.
+`pop` returns and removes the minimum object in the heap. If the heap is empty it throws a `NotSuchElementException`.
+`peek` similar to `pop`, returns the minimum object but it does not remove it from the `BinaryHeap`.
+`push` adds an element to the `BinaryHeap`.
+`count` returns the number of elements in the `BinaryHeap`.
+
+With the help of [jqwik](https://jqwik.net/) create a test that generates random inputs for your heap and ensures that the element returned by `pop` every time it is invoked is the minimum of the remaining elements in the heap.
+
+
+**NOTE:** 
+- Do not use any existing implementation, write your own code. 
+- Use the provided project template as a starting point. 
+- In the project you can launch the tests with `mvn test`.
+- You may reuse your binary heap code from the previous practical assignment.