merge sort

merge_sort.merge.py

def merge(left, right, a):
    i = j = k = 0
    while i < len(left) and j < len(right):
        if left[i] < right[j]:
            # min(left) < min(right)
            a[k] = left[i]
            i += 1
        else:
            # min(left) >= min(right)
            a[k] = right[j]
            j += 1
        k += 1

    # put the rest elements in "left" into a
    while i < len(left):
        a[k] = left[i]
        i += 1
        k += 1

    # put the rest elements in "right" into a
    while j < len(right):
        a[k] = right[j]
        j += 1
        k += 1