Create quick_sort.py

Author: Amogh Singhal

quick_sort.py

@@ -0,0 +1,47 @@
+def swap(a, b):
+  temp = a
+  a = b
+  b = temp
+
+def quick_sort(array):
+  quick_sort_helper(array, 0, len(array)-1)
+
+def quick_sort_helper(arr, first, last):
+  if first < last:
+    split_point = partition(arr, first, last)
+
+    quick_sort_helper(arr, first, split_point - 1)
+    quick_sort_helper(arr, split_point + 1, last)
+
+def partition(arr, first, last):
+  pivot = arr[first]
+
+  left = first + 1
+  right = last
+
+  done = False
+
+  while not done:
+    
+    # move left and right pointers to locate split_point
+    while left <= right and arr[left] <= pivot:
+      left += 1
+    while arr[right] >= pivot and right >= left:
+      right -= 1
+
+    # when both pointers cross each other
+    # we have located the split_point
+    if right < left:
+      done = True
+    else:
+      # swap the left and right elements
+      swap(arr[left], arr[right])
+
+  # swap the first and right elements
+  swap(arr[first], arr[right])
+
+  return right
+
+  array = [54,26,93,17,77,31,44,55,20]
+  quick_sort(array)
+  print(array)