I've been trying to run the quicksort with a switch to insertion sort when the sub array size is less than 10. So it turns out, i'm not getting a sorted list.
Where am i going wrong?
import random
import time
m = 0
def quicksort(numList, first, last):
if first<last:
sizeArr = last - first + 1
if(sizeArr < m):
insert_sort(numList, first, last)
else:
mid = partition(numList, first, last)
quicksort(numList, first, mid-1)
quicksort(numList, mid + 1, last)
def partition(numList, first, last):
piv = numList[last]
i = first-1
for j in range(first,last):
if numList[j] < piv:
i += 1
temp = numList[i]
numList[i] = numList[j]
numList[j] = temp
tempo = numList[i+1]
numList[i+1] = numList[last]
numList[last] = tempo
return i+1
def insert_sort(numList, first, last):
for x in range(first, last):
key = numList[x]
y = x-1
while y > -1 and numList[y]> key:
numList[y+1] = numList[y]
y = y-1
numList[y+1] = key
if __name__ == '__main__':
start = time.time()
numList = random.sample(range(5000), 100)
m = 10
quicksort(numList, 0, len(numList) - 1)
print numList
print "Time taken: " + str(time.time() - start)
input is some random array of sizes between 100 - 1000000. I'm using a random generator as you can see.
Please help me.
You have an off-by-one error in insert_sort
function. Iterate over range(first, last+1)
and it will sort correctly.
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