def merge_sort(arr, left, right):

if right <= left:

return

else:

merge_sort(arr, left, (left + right) // 2)

merge_sort(arr, (left + right) // 2 + 1, right)

merge(arr, left, (left + right) // 2, (left + right) // 2 + 1, right)

def merge(arr, left1, right1, left2, right2):

temp = [0] * (right2 - left1 + 1)

ptr = 0

ptr1 = left1

ptr2 = left2

for i in range(len(temp)):

# ptr2 >= right_size ptr1 < right1_size

if ptr2 > right2 or (ptr1 <= right1 and arr[ptr1] < arr[ptr2]) :

temp[i] = arr[ptr1]

ptr1 += 1

else:

temp[i] = arr[ptr2]

ptr2 += 1

for i in range(len(temp)):

arr[left1 + i] = temp[i]

merge_sort([ 10, 9, -2, -3, 1, -4, -2], 0, 6)