Insert sort

README.md

@@ -51,7 +51,14 @@
 - implements edge weights on edges in our graph  
 
 ## Binary Search Tree  
-- http://interactivepython.org/runestone/static/pythonds/Trees/SearchTreeImplementation.html
+- http://interactivepython.org/runestone/static/pythonds/Trees/SearchTreeImplementation.html  
+
+## Insert Sort  
+- implements insert sort  
+- compares each value in list with previous value
+- inserts number when it is no longer less than previous value  
+- best case is an already sorted list  
+- worst case is a reversed list
 
 ### Singly vs. Doubly Linked Lists  
 - A Singly Linked-List  

src/bst.py

@@ -264,3 +264,28 @@ def delete(self, val):
             else:
                 self.root = replacement
         self.length -= 1
+
+        def self_balancing(self):
+            cur = self.root
+            if self.balance(cur) <= 1 or self.balance(cur) >= -1:
+                return
+
+        def right_rotation(self, node):
+            parent = node.left
+            parent.right = node
+            return parent
+
+        def left_rotation(self, node):
+            parent = node.right
+            parent.left = node
+            return parent
+
+        def right_left_rotation(self, node):
+            node.right = self.right_rotation(node.right)
+            node = self.left_rotation(node)
+            return node
+
+        def left_right_rotation(self, node):
+            node.left = self.left_rotation(node.left)
+            node = self.right_rotation(node)
+            return node

src/insert_sort.py

@@ -0,0 +1,31 @@
+# -*- coding: utf-8 -*-
+import timeit
+
+
+BEST_CASE = [x for x in range(0, 1000)]
+WORST_CASE = BEST_CASE[::-1]
+
+
+def insert_sort(l):
+    """Sort a list by inserting values in order after comparing each value."""
+    if len(l) <= 1:
+        return
+    for idx in range(1, len(l)):
+        cur = l[idx]
+        spot = idx
+        while spot > 0 and l[spot - 1] > cur:
+            l[spot] = l[spot - 1]
+            spot = spot - 1
+        l[spot] = cur
+
+
+if __name__ == '__main__':
+    print("Best Case: a list already in order")
+    print("number of runs: 1000 / average time: " + str((timeit.Timer(
+        "insert_sort(BEST_CASE)", setup="from __main__ import insert_sort, BEST_CASE").timeit(
+            number=1000))/1000))
+    print("Worst Case: a list in reverse order")
+    print("number of runs: 1000 / average time: " + str(
+        (timeit.Timer(
+            "insert_sort(WORST_CASE)", setup="from __main__ import insert_sort, WORST_CASE").timeit(
+                number=1000))/1000))

src/test_insert_sort.py

@@ -0,0 +1,32 @@
+# -*- coding: utf-8 -*-
+from __future__ import unicode_literals
+import copy
+import random
+import pytest
+
+
+TEST_LIST = [
+    [], [8]
+]
+
+for x in range(0, 10):
+    y = (random.sample(range(100), random.randint(1, 50)))
+    TEST_LIST.append(y)
+
+
+@pytest.mark.parametrize('test_list', TEST_LIST)
+def test_insertion_sort_random(test_list):
+    from insert_sort import insert_sort
+    start_list = copy.copy(test_list)
+    insert_sort(test_list)
+    assert test_list == sorted(start_list)
+
+
+def test_best_case():
+    from insert_sort import BEST_CASE
+    assert isinstance(BEST_CASE, list)
+
+
+def test_worst_case():
+    from insert_sort import WORST_CASE
+    assert isinstance(WORST_CASE, list)