Shellsort implemented in python, ploted using matplotlib

shellsort.py

from random import randint
from timeit import timeit
import matplotlib.pyplot as plt

def reverseArray(lenght):
	a = []
	for i in range(lenght):
		a.append(lenght-i)
	return a

def randomArray(length):
	array = []
	tmp = 0
	while tmp < length:
		num = randint(1, length*10)
		if num not in array:
			array.append(num)
			tmp += 1
	return array

def shellsort(array):
	gap = len(array) // 2
	while gap > 0:
		for i in range(gap):
			for j in range(i+gap, len(array), gap):
				_tmp = array[j]
				pos = j
				while pos>=gap and array[pos] > array[pos-gap]:
					array[pos] = array[pos-gap]
					pos = pos-gap
				array[pos] = _tmp
		gap = gap // 2
	return array
  

timeRandom = []
timeReverse = []
lengths = []
elements = [1000, 3000, 6000, 9000, 12000, 15000, 18000, 21000, 24000]

def desenhaGrafico(xl = "Qnt. Elements(und)", yl = "Time(sec)"):
  
	plt.title('Shellsort Analysis', fontsize=20)
	plt.plot(lengths, timeRandom, label = "Random")
	plt.plot(lengths, timeReverse, label = "Reverse - Worse")
	legend = plt.legend(loc='upper left', shadow=True)
	frame = legend.get_frame()
	frame.set_facecolor('0.90')
	
	plt.xlabel(xl)
	plt.ylabel(yl)
	plt.show()	

def main():
	for _tmp in elements:
		lengths.append(_tmp)
		arrayRandom = randomArray(_tmp)
		arrayReverse = reverseArray(_tmp)
		timeRandom.append(timeit("shellsort({})".format(arrayRandom), 
			setup = "from __main__ import shellsort", number = 1))
		timeReverse.append(timeit("shellsort({})".format(arrayReverse), 
			setup = "from __main__ import shellsort", number = 1))
		
	desenhaGrafico()

if __name__ == "__main__":
  main()