* The original code did not consider the exit condition when the stations cannot perfectly cover the states_needed.
* The code in 09_dynamic_programming/python/01_longest_common_subsequence.py is completed. And the 02_longest_common_substring.py is added.
* Update 01_selection_sort.py
Updated last print statement for Python 3 print function.
* Update 01_countdown.py
Updated print statement to print function for Python 3.
* Update 05_quicksort.py
Updated print statement to print function for Python 3.
* Update 01_price_of_groceries.py
Condensed dictionary creation into one line, edited print statement to a print function for Python 3.
* Update 01_set_covering.py
Changed print statement to print function for Python 3.
* Update 01_binary_search.py
Changed print statements to print function for Python 3.
