Turbosort in python

https://www.codechef.com/problems/TSORT.

This is my solution for the problem, while running it with sample I am getting the expected output. But if i submit the solution i am getting a error, NZEC. what am i missing out here.

def quickSort(alist):
quickSortHelper(alist, 0, len(alist) - 1)
return 0

def quickSortHelper(alist,first,last):
if first<last:
splitpoint = partition(alist,first,last)
quickSortHelper(alist,first,splitpoint-1)
quickSortHelper(alist,splitpoint+1,last)
return 0;

def partition(alist,first,last):
partitionValue = alist[first]

done=False
leftmark = first + 1
rightmark = last

while not done:
    while leftmark<=rightmark and alist[leftmark]<=partitionValue:
        leftmark = leftmark +1
    while rightmark>=leftmark and alist[rightmark]>=partitionValue:
        rightmark=rightmark-1
    if leftmark>rightmark:
        done=True
    else:
      alist[rightmark],alist[leftmark] = alist[leftmark],alist[rightmark]
      
alist[first],alist[rightmark]=alist[rightmark],alist[first]
return rightmark

t=int(input())
alist=[]
for i in range(t):
alist.append(int(input()))
quickSort(alist)
for i in range(len(alist)):
print(alist[i])