# -*- coding: utf-8 -*-
# UWAGA: to jest wersja dla python 3
def mergeSort(arr): 
    if len(arr) >1: 
        mid = len(arr)//2
        L = arr[:mid]
        R = arr[mid:]
  
        mergeSort(L) 
        mergeSort(R)

        merge(L,R,arr)

def merge(L,R,arr):
          
        i = j = k = 0
        # scalanie
        while i < len(L) and j < len(R): 
            if L[i] < R[j]: 
                arr[k] = L[i] 
                i+=1
            else: 
                arr[k] = R[j] 
                j+=1
            k+=1
          
        # resztki
        while i < len(L): 
            arr[k] = L[i] 
            i+=1
            k+=1
          
        while j < len(R): 
            arr[k] = R[j] 
            j+=1
            k+=1
  
# Wypisz liste
def printList(arr): 
    for i in range(len(arr)):         
        print(arr[i],end=" ") 
    print() 
  
# Test
if __name__ == '__main__': 
    arr = [12, 11, 13, 5, 6, 7]  
    print ("Given array is", end="\n")  
    printList(arr) 
    mergeSort(arr) 
    print("Sorted array is: ", end="\n") 
    printList(arr)