Python Program for Quicksort

In this article, we will learn about the solution to the problem statement given below.

Problem statement − We are given an array, we need to sort it using the concept of quicksort

Here we first partition the array and sort the separate partition to get the sorted array.

Now let’s observe the solution in the implementation below −

Example

 Live Demo

# divide function
def partition(arr,low,high):
   i = ( low-1 )
   pivot = arr[high] # pivot element
   for j in range(low , high):
      # If current element is smaller
      if arr[j] <= pivot:
         # increment
         i = i+1
         arr[i],arr[j] = arr[j],arr[i]
   arr[i+1],arr[high] = arr[high],arr[i+1]
   return ( i+1 )
# sort
def quickSort(arr,low,high):
   if low < high:
      # index
      pi = partition(arr,low,high)
      # sort the partitions
      quickSort(arr, low, pi-1)
      quickSort(arr, pi+1, high)
# main
arr = [2,5,3,8,6,5,4,7]
n = len(arr)
quickSort(arr,0,n-1)
print ("Sorted array is:")
for i in range(n):
   print (arr[i],end=" ")

Output

Sorted array is
2 3 4 5 5 6 7 8

All the variables are declared in the local scope and their references are seen in the figure above.

Conclusion

In this article, we have learned about how we can make a Python Program for QuickSort