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+"""Perl weekly challenge 187 - Task 1: Days Together.
+
+Two friends, Foo and Bar gone on holidays seperately to the same city.
+You are given their schedule i.e. 'start date' and 'end date'.
+To keep the task simple, the date is in the form 'DD-MM' and all dates
+belong to the same calendar year i.e. between '01-01' and '31-12'. Also
+the year is 'non-leap year'. Also both dates are inclusive.
+Write a script to find out for the given schedule, how many days they
+spent together in the city, if at all.
+
+https://theweeklychallenge.org/blog/perl-weekly-challenge-187/
+"""
+import datetime
+import unittest
+
+NONE_LEAP_YEAR = 2022
+
+
+def to_day_of_year(day_mon: str, year: int = NONE_LEAP_YEAR) -> int:
+    """Convert a "DD-MM" date string to the day of the year.
+
+    All dates belong to the same calendar year, and it isn't a "leap year".
+
+    :param day_mon: date in "DD-MM" format
+    :param year: year. default is a non-leap year
+    :return: day of the year
+    """
+    date = datetime.date(year, int(day_mon[3:]), int(day_mon[0:2]))
+    return int(f"{date:%j}")
+
+
+def days_together(foo: dict, bar: dict) -> int:
+    """Find how many days are spent together for the given schedules.
+
+    :param foo: schedule of 1st person
+    :param bar:schedule of 2nd person
+    :return: number of pent together days
+    """
+    foo_sd, foo_ed = to_day_of_year(foo['SD']), to_day_of_year(foo['ED'])
+    bar_sd, bar_ed = to_day_of_year(bar['SD']), to_day_of_year(bar['ED'])
+    if foo_sd > bar_ed or foo_ed < bar_sd:
+        return 0
+    return min(foo_ed, bar_ed) - max(foo_sd, bar_sd) + 1
+
+
+class TestDaysTogether(unittest.TestCase):
+
+    def test_days_together(self):
+        cases = (
+            {'args': ({'SD': '12-01', 'ED': '20-01'}, {'SD': '15-01', 'ED': '18-01'}), 'expected': 4},
+            {'args': ({'SD': '02-03', 'ED': '12-03'}, {'SD': '13-03', 'ED': '14-03'}), 'expected': 0},
+            {'args': ({'SD': '02-03', 'ED': '12-03'}, {'SD': '11-03', 'ED': '15-03'}), 'expected': 2},
+            {'args': ({'SD': '30-03', 'ED': '05-04'}, {'SD': '28-03', 'ED': '02-04'}), 'expected': 4},
+        )
+        for case in cases:
+            self.assertEqual(days_together(*case['args']), case['expected'], str(case['args']))
+
+
+if __name__ == '__main__':
+    unittest.main()