From 22a8553f11c3cb527ac054fb422f8284baa48db3 Mon Sep 17 00:00:00 2001
From: UN997 <udaynair2797@gmail.com>
Date: Thu, 4 Oct 2018 01:27:13 +0530
Subject: [PATCH] Added quick sort

---
 sorting/quick_sort.py | 42 ++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 42 insertions(+)
 create mode 100644 sorting/quick_sort.py

diff --git a/sorting/quick_sort.py b/sorting/quick_sort.py
new file mode 100644
index 0000000..0ad549c
--- /dev/null
+++ b/sorting/quick_sort.py
@@ -0,0 +1,42 @@
+
+def quickSort(alist):
+
+  quickSortHelper(alist,0,len(alist)-1)
+
+def quickSortHelper(alist,first,last):
+
+  if first<last:
+      splitpoint = partition(alist,first,last)
+      quickSortHelper(alist,first,splitpoint-1)
+      quickSortHelper(alist,splitpoint+1,last)
+
+def partition(alist,first,last):
+
+  pivotvalue = alist[first]
+  leftmark = first+1
+  rightmark = last
+  done = False
+
+  while not done:
+      while leftmark <= rightmark and alist[leftmark] <= pivotvalue:
+          leftmark = leftmark + 1
+
+      while alist[rightmark] >= pivotvalue and rightmark >= leftmark:
+          rightmark = rightmark -1
+
+      if rightmark < leftmark:
+          done = True
+      else:
+          temp = alist[leftmark]
+          alist[leftmark] = alist[rightmark]
+          alist[rightmark] = temp
+
+  temp = alist[first]
+  alist[first] = alist[rightmark]
+  alist[rightmark] = temp
+
+  return rightmark
+
+alist = [54,26,93,17,77,31,44,55,20]
+quickSort(alist)
+print(alist)
\ No newline at end of file