[Feature] Added heapsort with heapq built-in and with custom heap.

Author: exterkamp

README.md

@@ -27,6 +27,7 @@ $ coverage report -m
 * [Quicksort](sorts/quicksort.py)
 * [Mergesort](sorts/mergesort.py)
 * [Radixsort](sorts/radixsort.py)
+* [Heapsort](sorts/heapsort.py)
 
 ### Searching Algorithms
 * [BinarySearch](searches/binary_search.py)

sorts/heapsort.py

@@ -0,0 +1,28 @@
+from copy import deepcopy
+from heapq import heapify, heappop
+from structures.heap import Heap
+
+def heap_sort(lst:list):
+    copy_list = deepcopy(lst)
+    heapify(copy_list)
+    return [heappop(copy_list) for i in range(len(copy_list))]
+
+def max_heap_sort(lst:list):
+    copy_list = deepcopy(lst)
+    # make all elements negative, so heap is a max heap
+    copy_list = list(map(lambda x: x * -1, copy_list))
+    heapify(copy_list)
+    copy_list = [heappop(copy_list) for i in range(len(copy_list))]
+    copy_list =  list(map(lambda x: x * -1, copy_list))
+    return copy_list
+
+def custom_heap_sort(lst:list,sort='min'):
+    copy_list = deepcopy(lst)
+    if sort == 'max':
+        copy_list = list(map(lambda x: x * -1, copy_list))
+    heap = Heap()
+    heap.build(copy_list)
+    sorted_list = [heap.delete_min() for i in range(heap.size())]
+    if sort == 'max':
+        sorted_list = list(map(lambda x: x * -1, sorted_list))
+    return sorted_list

tests/test_heap_sort.py

@@ -0,0 +1,20 @@
+import unittest
+from sorts.heapsort import heap_sort, max_heap_sort, custom_heap_sort
+
+class TestHeapSort(unittest.TestCase):
+
+    random_list = [7, 9, 3, 24, 84, 12, 3, 4, 20, 39, 8, 2, 4, 99, 24, 4]
+
+    sorted_list = [2, 3, 3, 4, 4, 4, 7, 8, 9, 12, 20, 24, 24, 39, 84, 99]
+
+    def test_heap_sort(self):
+        self.assertEqual(self.sorted_list, heap_sort(self.random_list))
+
+    def test_max_heap_sort(self):
+        self.assertEqual(self.sorted_list[::-1], max_heap_sort(self.random_list))
+    
+    def test_heap_sort_custom(self):
+        self.assertEqual(self.sorted_list, custom_heap_sort(self.random_list))
+    
+    def test_heap_max_sort_custom(self):
+        self.assertEqual(self.sorted_list[::-1], custom_heap_sort(self.random_list, 'max'))