Homework 6
		Due Wednesday, Nov. 4 (a week and a day)

    Go to http://codingbat.com/python and do the exercises.  In each case, your
solution should be able to produce an answer using at most two lines of code
in the body.  (Using a ';' to combine two lines doesn't count.)
    The exercise sum67 is an exception.  You may use up to four lines in the
body.
    In order to produce solutions in only two lines of code, you will
probably need to use list comprehensions.  There is a subdirectory
/course/cs5600f15/python , which has information on getting started in
Python, and in particular, on list comprehensions.  You'll also want
to take advantage of such Python built-in functions as:
 * len(), range()
 * max(), min(), sum(), pow(), abs()
 * all(), any()
 * set(), list()    [Useful, because a set eliminates any duplicates in a list]
 * sorted(), reversed()
 * zip()
 * etc.

As an example, consider the following function, whose body is only one line:

def sum_of_squares_of_odd_numbers(max_int):
  return sum([i**2 for i in range(20) if i % 2 == 1])

Now, it's your turn:

    Python > List-1 > sum3
    Python > List-1 > rotate_left3
    Python > List-1 > max_end3
    Python > List-1 > make_ends
    Python > List-1 > has23
    Python > List-2 > count_events
    Python > List-2 > sum13
    Python > List-2 > big_diff
    Python > List-2 > sum67
    Python > List-2 > centered_average
    Python > List-2 > has22
    Python > String-1 > extra_end 
    Python > String-1 > without_end 
    Python > String-2 > double_char
    Python > String-2 > count_code
    Python > String-2 > count_hi
    Python > String-2 > end_other
    Python > String-2 > cat_dog
    Python > String-2 > xyz_there