CODE EXAMPLE FOR PYTHON

merge sort function

def merge_sort(arr):
    """Execute the merge sort algorithm"""
    if len(arr) > 1:
        # recursive case
        mid = len(arr) // 2 # find the midpoint of the array
        l = arr[:mid] # define the left half of the array
        r = arr[mid:] # define the right half of the array

        l = merge_sort(l) # sort the left half by calling this function
        r = merge_sort(r) # sort the right half by calling this function

        # now merge the two lists
        merged = [] # define an empty merged array
        while len(l) > 0 and len(r) > 0:
            # compare the heads of the left and right array
            if l[0] <= r[0]:
                # if the head of the left list is smaller than the head of the right list
                # pop the head of the left list and append it to the merged list
                merged.append(l.pop(0))
            else:
                # otherwise, pop the head of the right list and append that
                merged.append(r.pop(0))

        # add any elements remaining in the left or right list to the merged list
        merged = merged + l + r

        return merged
    else:
        # base case
        return arr