Binary.py

# Recall in Worked Example 5.2.5 that we showed you the code
# for two versions of binary_search: one using recursion, one
# using loops. For this problem, use the recursive one.
#
# In this problem, we want to implement a new version of
# binary_search, called binary_search_year. binary_search_year
# will take in two parameters: a list of instances of Date,
# and a year as an integer. It will return True if any date
# in the list occurred within that year, False if not.
#
# For example, imagine if listOfDates had three instances of
# date: one for January 1st 2016, one for January 1st 2017,
# and one for January 1st 2018. Then:
#
#  binary_search_year(listOfDates, 2016) -> True
#  binary_search_year(listOfDates, 2015) -> False
#
# You should not assume that the list is pre-sorted, but you
# should know that the sort() method works on lists of dates.
#
# Instances of the Date class have three attributes: year,
# month, and day. You can access them directly, you don't
# have to use getters (e.g. myDate.month will access the
# month of myDate).
#
# You may copy the code from Worked Example 5.2.5 and modify
# it instead of starting from scratch. You must implement
# binary_search_year recursively.
#
# Don't move this line:
from datetime import date


# Write your code here!


def binary_search_year(list_dates, dates):
    list_dates.sort()
    if len(list_dates) == 0:
        return False
    mid = len(list_dates) // 2
    if list_dates[mid].year == dates:
        return True
    elif dates < list_dates[mid].year:
        return binary_search_year(list_dates[:mid], dates)

    else:
        return binary_search_year(list_dates[mid + 1:], dates)


# Below are some lines of code that will test your function.
# You can change the value of the variable(s) to test your
# function with different inputs.
#
# If your function works correctly, this will originally
# print: True, then False
listOfDates = [date(2016, 11, 26), date(2014, 11, 29),
               date(2008, 11, 29), date(2000, 11, 25),
               date(1999, 11, 27), date(1998, 11, 28),
               date(1990, 12, 1), date(1989, 12, 2),
               date(1985, 11, 30)]

print(binary_search_year(listOfDates, 2016))
print(binary_search_year(listOfDates, 2007))