def mergeSort(array):
    length = len(array)
    if length <= 1: return
    
    middle = length // 2
    leftArray = array[:middle]
    rightArray = array[middle:]
 
    mergeSort(leftArray)
    mergeSort(rightArray)
    merge(leftArray, rightArray, array)


def merge(leftArray, rightArray, array):
    leftLength = len(leftArray)
    rightLength = len(rightArray)
    i = 0
    l = 0
    r = 0
    
    while l < leftLength and r < rightLength:
        if leftArray[l] < rightArray[r]:
            array[i] = leftArray[l]
            l += 1
        else:
            array[i] = rightArray[r]
            r += 1
            
        i += 1;
    
    if l < leftLength:
        array[i] = leftArray[l]
            
    
if __name__ == '__main__':
    arr = [12, 11, 5, 6, 7, 194]
    print(f'Given array is: \n{arr}');
    mergeSort(arr);
    print(f'Sorted array is: \n{arr}')