Merge pull request #91 from gillesigot/master

Added Python quick sort

Author: master-fury

Arrays-Sorting/src/Quick_sort/quicksort.py

@@ -0,0 +1,37 @@
+def quickSort(arr):
+    """Apply quick sort on the given array
+
+    :param arr: the array to sort
+    :type arr: list
+    """
+    less = []
+    pivotList = []
+    more = []
+    if len(arr) <= 1:
+        return arr
+    else:
+        pivot = arr[0]
+        for i in arr:
+            if i < pivot:
+                less.append(i)
+            elif i > pivot:
+                more.append(i)
+            else:
+                pivotList.append(i)
+        less = quickSort(less)
+        more = quickSort(more)
+        return less + pivotList + more
+
+# Unit test
+a = [4, 65, 2, -31, 0, 99, 83, 782, 1]  # The array to sort
+a = quickSort(a)
+assert all(a[i] <= a[i+1] for i in range(len(a)-1))  # Assert array is sorted
+
+# Quick sort: Quicksort is a comparison sort, meaning that it can 
+# sort items of any type for which a "less-than" relation is defined. 
+# In efficient implementations it is not a stable sort, meaning 
+# that the relative order of equal sort items is not preserved. 
+# Quicksort can operate in-place on an array, requiring small 
+# additional amounts of memory to perform the sorting. It is very 
+# similar to selection sort, except that it does not always choose 
+# worst-case partition.