HackerRank: merge sort function https://repl.it/EVhs/13

merge-sort.py

# MergeSort Recursive Solution
# Python

def Merge(left, right, original):
  left_len = len(left)
  right_len = len(right)
  left_index = 0
  right_index = 0
  original_index = 0
  
  while left_index < left_len and right_index < right_len:
    print('left ' + str(left))
    print('right ' + str(right))
    print('original ' + str(original))
    print('\n')
    if left[left_index] <= right[right_index]:
      original[original_index] = left[left_index]
      left_index = left_index + 1
    else:      
      original[original_index] = right[right_index]
      right_index = right_index + 1
      
    original_index = original_index + 1   
  
  while left_index < left_len:
    original[original_index] = left[left_index]
    original_index = original_index + 1
    left_index = left_index + 1
    
  while right_index < right_len:
    original[original_index] = right[right_index]
    original_index = original_index + 1
    right_index = right_index + 1  


def MergeSort(original):
  og_len = len(original)
  if og_len < 2:
    return
  
  mid = int(og_len/2)
  left = list(original[0:mid])
  right = list(original[mid:og_len])

  MergeSort(left)
  MergeSort(right)
  Merge(left,right,original)
  
    
original = [5,3,6,2,-9]

print('before' + str(original))
MergeSort(original)
print('after' + str(original))