mergeSort

#!/usr/bin/env python3


def e_cmp(element_1: int, element_2: int, descend: bool = False) -> bool:
    """
    Compare the value of the two input value.
    :rtype: bool
    :param element_1:
    :param element_2:
    :param descend:
    :return:
    """
    if descend:
        return element_1 > element_2
    else:
        return element_1 <= element_2


def merge(list1: list, list2: list, descend: bool = False) -> list:
    """
    Sort 2 lists by merging in ascending (descend == True)
    or descending (descend == False) order.
    :rtype: list
    :param list1:
    :param list2:
    :param descend:
    :return:
    """
    iter1, iter2 = 0, 0
    result = list()
    while (iter1 < len(list1)) & (iter2 < len(list2)):
        if e_cmp(list1[iter1], list2[iter2], descend):
            result.append(list1[iter1])
            iter1 += 1
        else:
            result.append(list2[iter2])
            iter2 += 1
    if list1:
        result.extend(list1[iter1:])
    if list2:
        result.extend(list2[iter2:])
    return result


def merge_split(origin_list: list, descend: bool = False) -> list:
    """
    Construct the correct call architecture of
    merge in ascending (descend == true)
    or descending (descend != 1) order.
    :rtype: list
    :param origin_list:
    :param descend:
    :return:
    """
    if len(origin_list) <= 1:
        return origin_list
    tmp_list = list()
    new_list = list()
    for e in origin_list:
        tmp_list.append(e)
        if len(tmp_list) >= 2:
            new_list.append(merge(tmp_list[0], tmp_list[1], descend))
            tmp_list = list()
    if tmp_list:
        new_list.append(merge(tmp_list[0], [], descend))
    return merge_split(new_list, descend)


def merge_sort(origin_list: list, descend: bool = False) -> list:
    """
    Split the array into as many array that the original array
    contain then call the mergeSplit function.
    :rtype: list
    :param origin_list:
    :param descend:
    :return:
    """
    result = list()
    for e in origin_list:
        result.append([e])
    return merge_split(result, descend)[0]