quick_sort.py

def partition(array, first, last):
	pivot = array[last]
	print "Pivot: ", pivot
	index = first
	for j in range(first,last):
		print "Comparing ", array[j]," and ",pivot
		if array[j] <= pivot:
			print "Swapping ",array[j], " and ", array[index]
			temp = array[j]
			array[j] = array[index]
			array[index] = temp
			index += 1
			print "After Swapping: ",array
	print "\nPlacing Pivot:"
	temp_pivot = array[index]
	array[index] = array[last]
	array[last] = temp_pivot
	print array
	return index

			


def quicksort(array, first, last):
	if first < last:
		print "Partition : ", array[first:last + 1]
		pivot_index = partition(array, first, last)
		print "Left Partition : ", array[first : pivot_index]
		quicksort(array, first, pivot_index - 1)
		print "Right Partition : ", array[pivot_index + 1: last]
		quicksort(array, pivot_index + 1, last)


array = [50, 60, 20, 10, 80, 90, 30]

print "Unsorted Array:",array

quicksort(array, 0, len(array) - 1)
#print partition(array, 0, len(array) - 1)

print array