QuickSort

QuickSort.py

#Author: VikasKumar<vikaskumar185@gmail.com>
#Time Complexity:
    #Best Case  :  O(nlogn)
    #Worst Case :  O(n^2)
    #Suggestion :  Always use middle element as Pivot
   
#QuickSort
def QuickSort(arr,low,high):
   if low<high:
       j = Partition(arr,low,high)
       QuickSort(arr,low,j-1)
       QuickSort(arr,j+1,high)


def Partition(arr,low,high):
   pivot = arr[low]
   i = low+1
   j = high

   flag = False
   while not flag:

       while i <= j and arr[i] <= pivot:
           i = i + 1

       while arr[j] >= pivot and j >= i:
           j = j -1

       if j < i:
           flag = True
       else:
           temp = arr[i]
           arr[i] = arr[j]
           arr[j] = temp

   temp = arr[low]
   arr[low] = arr[j]
   arr[j] = temp

   return j

arr = [4,8,5,1,2,6,3,9,7]
QuickSort(arr,0,len(arr)-1)
print(arr)