trying to implement some stuff from data structures class

DataStructuresPractice/BinaryHeap.java

@@ -0,0 +1,20 @@
+public class BinaryHeap<T> {
+    private DynamicResizingArray<T> array = new DynamicResizingArray<T>();
+
+    public BinaryHeap() {
+        // nothing
+    }
+
+    public T extractMax() {
+        return null; // TODO
+    }
+
+    public void insert(T item) {
+        // put it at the end and then swap up with parent as much as needed for heap property
+        // TODO
+    }
+
+    public static void main(String[] args) {
+        BinaryHeap heap = new BinaryHeap();
+    }
+}

DataStructuresPractice/DynamicResizingArray.java

@@ -0,0 +1,40 @@
+public class DynamicResizingArray<T> {
+    private T[] array = (T[]) new Object[1];
+    private int capacity = 1;
+    public int length = 0;
+
+    public DynamicResizingArray() {
+        // nothing
+    }
+
+    public void insert(T item) {
+        array[length] = item;
+        length++;
+        resize();
+    }
+
+    private void resize() {
+        if (length == capacity) {
+            // resize to double
+            int newCapacity = 2 * capacity;
+            T[] newArray = (T[]) new Object[newCapacity];
+            copyItems(array, newArray);
+            array = newArray;
+        }
+    }
+
+    private void copyItems(T[] array, T[] newArray) {
+        for (int i = 0; i < array.length; i++) {
+            newArray[i] = array[i];
+        }
+    }
+
+    public void push(T item) {
+        int index = length;
+        setItem(index, item);
+    }
+
+    public void setItem(int index, T item) {
+        array[index] = item;
+    }
+}