#!/usr/bin/env python
#Author: Shriphani Palakodety
#Mail: shriphani@shriphani.com
#Blog: http://shriphani.com/blog

def makeSubLists(num_list):
    '''Divide given numbers into groups of two'''
    lists = []
    i = 0
    while i < len(num_list):
	lists.append(num_list[i:i+2])
	i += 2
    return lists

def sortTwos(num_list):
    '''sort the lists returned by makeSubLists()'''
    try:	
	if num_list[0] >= num_list[1]:
	    num_list.reverse()
    except IndexError:
	    pass
    return num_list

def recurMerge(list1, list2, merged_list=[]):
    '''recursively merge the two given lists'''
    if len(list1) == 0:
	merged_list += list2
	return merged_list
    elif len(list2) == 0:
	merged_list += list1
	return merged_list
    else:
	if list1[0] <= list2[0]:
	    merged_list.append(list1[0])
	    list1.pop(0)
	else:
	    merged_list.append(list2[0])
	    list2.pop(0)
	return recurMerge(list1, list2, merged_list)

def merge(singletons):
    '''supply lists to recurMerge and recursively sort'''
    final_list = []
    if len(singletons) == 1:
	return singletons[0]
    else:
	i = 0
	while i < len(singletons):
	    final_list.append(recurMerge(singletons[i], singletons[i+1], []))
	    i += 2
	singletons = final_list
	return merge(singletons)