add quicksort

chapter4/quicksort.py

@@ -0,0 +1,32 @@
+def quicksort(arr):
+    if len(arr) < 2:
+        return arr
+
+
+import logging
+import random
+
+logging.basicConfig(level=logging.DEBUG)
+logger = logging.getLogger(__name__)
+
+
+def quicksort(arr):
+    # base case. arr of length 0 or 1 don't need sorting, so return them as is
+    if len(arr) < 2:
+        return arr
+
+    pivot = arr[0]
+
+    # split arr into 3 parts, [less] | [pivot] | [greater]
+    less = [i for i in arr[1:] if i <= pivot]
+    greater = [i for i in arr[1:] if i > pivot]
+
+    return quicksort(less) + [pivot] + quicksort(greater)
+
+
+LOWER = 0
+UPPER = 100
+SAMPLE_SIZE = 15
+numbers = random.sample(range(LOWER, UPPER), SAMPLE_SIZE)
+logging.debug(numbers)
+print(quicksort(numbers))