我正在寻找一种优雅的算法来检查两个每年重复的时间段是否重叠。该时间段与年份无关,但可以预期每年都是闰年。
例如,时间段A =(3月1日至5月1日),时间段B =(4月1日至9月1日)重叠。 同样,时间段A =(10月1日至2月1日)和时间段B =(1月1日至3月1日)也会重叠。
然而,我发现这比我预想的要困难得多。复杂性来自跨越年末的时间段。
我有一个可行的解决方案(请参见下面的
注意:我已经用Python编写了代码,但理想情况下解决方案不应太依赖于Python(即不使用通常只在Python中提供的函数,而不是在C或C#中)。
例如,时间段A =(3月1日至5月1日),时间段B =(4月1日至9月1日)重叠。 同样,时间段A =(10月1日至2月1日)和时间段B =(1月1日至3月1日)也会重叠。
然而,我发现这比我预想的要困难得多。复杂性来自跨越年末的时间段。
我有一个可行的解决方案(请参见下面的
doesOverlap(A,B)
方法),但我发现它很复杂。# for the rest of the MWE context code, see further
# WORKING, but a bit convulted
def doesOverlap(A, B):
'''returns True if yearly period A and B have overlapping dates'''
# list to track if day in year is part of a period A
# (this could probably be done a bit cheaper with a dictionary of tuples, but not relevant for my question)
yeardayCovered = [False for x in range(366)] # leap year
# mark the days of A
for d in range(A.start, A.start + A.length):
yeardayCovered[d % 366] = True
# now check each of the days in B with A
for d in range(B.start, B.start + B.length):
if yeardayCovered[d % 366]:
return True
return False
我相信可以通过少量的检查和更加优雅的方式来实现。我尝试将开始时间中的一个设置为零偏移量,应用一些模运算,然后执行常规(非循环)范围重叠检查(算法检测重叠期间),但我并没有让所有的测试案例都正常工作。
#NOT WORKING CORRECTLY!!
def doesOverlap(A, B):
'''determines if two yearly periods have overlapping dates'''
Astart = A.start
Astop = A.stop
Bstart = B.start
Bstop = B.stop
# start day counting at Astart, at 0
offset = Astart
Astart = 0
Astop = (Astop - offset) % 366
Bstart = (Bstart - offset) % 366
Bstop = (Bstop - offset) % 366
# overlap?
# https://dev59.com/2mYr5IYBdhLWcg3wpLr9#13513973
return (Astart <= Bstop and Bstart <= Astop)
注意:我已经用Python编写了代码,但理想情况下解决方案不应太依赖于Python(即不使用通常只在Python中提供的函数,而不是在C或C#中)。
# MWE (Minimal Working Example)
import datetime
import unittest
class TimePeriod:
def __init__(self, startDay, startMonth, stopDay, stopMonth):
self.startDay = startDay
self.startMonth = startMonth
self.stopDay = stopDay
self.stopMonth = stopMonth
def __repr__(self):
return "From " + str(self.startDay) + "/" + str(self.startMonth) + " to " + \
str(self.stopDay) + "/" + str(self.stopMonth)
def _dayOfYear(self, d, m, y=2012):
'''2012 = leap year'''
date1 = datetime.date(year=y, day=d, month=m)
return date1.timetuple().tm_yday
@property
def start(self):
'''day of year of start of period, zero-based for easier modulo operations! '''
return self._dayOfYear(self.startDay, self.startMonth) - 1
@property
def stop(self):
'''day of year of stop of period, zero-based for easier modulo operations! '''
return self._dayOfYear(self.stopDay, self.stopMonth) - 1
@property
def length(self):
'''number of days in the time period'''
_length = (self.stop - self.start) % 366 + 1
return _length
def doesOverlap(A, B):
# code from above goes here
class TestPeriods(unittest.TestCase):
pass
def test_generator(a, b, c):
def test(self):
self.assertEqual(doesOverlap(a, b), c)
return test
if __name__ == '__main__':
#some unit tests, probably not complete coverage of all edge cases though
tests = [["max", TimePeriod(1, 1, 31, 12), TimePeriod(1, 1, 1, 1), True],
["BinA", TimePeriod(1, 3, 1, 11), TimePeriod(1, 5, 1, 10), True],
["BoverEndA", TimePeriod(1, 1, 1, 2), TimePeriod(10, 1, 3, 3), True],
["BafterA", TimePeriod(1, 1, 1, 2), TimePeriod(2, 2, 3, 3), False],
["sBoutA", TimePeriod(1, 12, 2, 5), TimePeriod(1, 6, 1, 7), False],
["sBoverBeginA", TimePeriod(1, 11, 2, 5), TimePeriod(1, 10, 1, 12), True],
["sBinA", TimePeriod(1, 11, 2, 5), TimePeriod(1, 1, 1, 2), True],
["sBinA2", TimePeriod(1, 11, 2, 5), TimePeriod(1, 12, 10, 12), True],
["sBinA3", TimePeriod(1, 11, 2, 5), TimePeriod(1, 12, 1, 2), True],
["sBoverBeginA", TimePeriod(1, 11, 2, 5), TimePeriod(1, 10, 1, 12), True],
["Leap", TimePeriod(29, 2, 1, 4), TimePeriod(1, 10, 1, 12), False],
["BtouchEndA", TimePeriod(1, 2, 1, 2), TimePeriod(1, 2, 1, 3), True]]
for i, t in enumerate(tests):
test_name = 'test_%s' % t[0]
test = test_generator(t[1], t[2], t[3])
setattr(TestPeriods, test_name, test)
# unittest.main()
suite = unittest.TestLoader().loadTestsFromTestCase(TestPeriods)
unittest.TextTestRunner(verbosity=2).run(suite)