Tiffany Harper :: Completed all methods

heaps/heap_sort.py

@@ -1,8 +1,18 @@
+from min_heap import MinHeap
 
 
 def heap_sort(list):
     """ This method uses a heap to sort an array.
         Time Complexity:  ?
         Space Complexity: ?
     """
-    pass
+    heap = MinHeap()
+
+    sorted_array = []
+    for num in list:
+        heap.add(num)
+
+    while not heap.empty():
+        sorted_array.append(heap.pop())
+
+    return sorted_array

heaps/min_heap.py

@@ -1,5 +1,5 @@
+
 class HeapNode:
-
     def __init__(self, key, value):
         self.key = key
         self.value = value
@@ -10,67 +10,95 @@ def __str__(self):
     def __repr__(self):
         return str(self.value)
 
+
 class MinHeap:
 
     def __init__(self):
         self.store = []
 
-
-    def add(self, key, value = None):
+    def add(self, key, value=None):
         """ This method adds a HeapNode instance to the heap
             If value == None the new node's value should be set to key
             Time Complexity: ?
             Space Complexity: ?
         """
-        pass
+        new_node = HeapNode(key, value)
+        if value == None:
+            new_node.value = key
+        self.store.append(new_node)
+        if len(self.store) > 1:
+            index = len(self.store) - 1
+            self.heap_up(index)
 
     def remove(self):
         """ This method removes and returns an element from the heap
             maintaining the heap structure
             Time Complexity: ?
             Space Complexity: ?
         """
-        pass
-
+        if self.empty():
+            return None
+        # root_node_index = 0
+        # last_node_index = len(self.store) - 1
+        self.swap(0, len(self.store)-1)
+        # storing this node to remove later
+        node_to_remove = self.store.pop()
+        self.heap_down(0)
+        return node_to_remove.value
 
-
     def __str__(self):
         """ This method lets you print the heap, when you're testing your app.
         """
         if len(self.store) == 0:
             return "[]"
         return f"[{', '.join([str(element) for element in self.store])}]"
 
-
     def empty(self):
         """ This method returns true if the heap is empty
             Time complexity: ?
             Space complexity: ?
         """
-        pass
-
+        return len(self.store) == 0
 
     def heap_up(self, index):
         """ This helper method takes an index and
-            moves the corresponding element up the heap, if 
+            moves the corresponding element up the heap, if
             it is less than it's parent node until the Heap
             property is reestablished.
-            
+
             This could be **very** helpful for the add method.
             Time complexity: ?
             Space complexity: ?
         """
-        pass
+        if index == 0:
+            return
+        parent_idx = (index - 1) // 2
+        if self.store[parent_idx].key > self.store[index].key:
+            self.swap(parent_idx, index)
+            self.heap_up(parent_idx)
 
     def heap_down(self, index):
-        """ This helper method takes an index and 
-            moves the corresponding element down the heap if it's 
+        """ This helper method takes an index and
+            moves the corresponding element down the heap if it's
             larger than either of its children and continues until
             the heap property is reestablished.
         """
-        pass
+        heap = self.store
+        left_child_idx = (index * 2) + 1
+        right_child_idx = (index * 2) + 2
+        if left_child_idx < len(heap):
+            if right_child_idx < len(heap):
+                if heap[left_child_idx].key < heap[right_child_idx].key:
+                    smaller = left_child_idx
+                else:
+                    smaller = right_child_idx
+            else:
+                # when there is no right child
+                smaller = left_child_idx
+            if heap[index].key > heap[smaller].key:
+                self.swap(index, smaller)
+                self.heap_down(smaller)
 
-
     def swap(self, index_1, index_2):
         """ Swaps two elements in self.store
             at index_1 and index_2