mirror of
https://github.com/TheAlgorithms/Python.git
synced 2024-11-24 05:21:09 +00:00
bc8df6de31
* [pre-commit.ci] pre-commit autoupdate updates: - [github.com/astral-sh/ruff-pre-commit: v0.2.2 → v0.3.2](https://github.com/astral-sh/ruff-pre-commit/compare/v0.2.2...v0.3.2) - [github.com/pre-commit/mirrors-mypy: v1.8.0 → v1.9.0](https://github.com/pre-commit/mirrors-mypy/compare/v1.8.0...v1.9.0) * [pre-commit.ci] auto fixes from pre-commit.com hooks for more information, see https://pre-commit.ci --------- Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>
61 lines
1.8 KiB
Python
61 lines
1.8 KiB
Python
"""
|
|
https://en.wikipedia.org/wiki/Computus#Gauss'_Easter_algorithm
|
|
"""
|
|
|
|
import math
|
|
from datetime import datetime, timedelta
|
|
|
|
|
|
def gauss_easter(year: int) -> datetime:
|
|
"""
|
|
Calculation Gregorian easter date for given year
|
|
|
|
>>> gauss_easter(2007)
|
|
datetime.datetime(2007, 4, 8, 0, 0)
|
|
|
|
>>> gauss_easter(2008)
|
|
datetime.datetime(2008, 3, 23, 0, 0)
|
|
|
|
>>> gauss_easter(2020)
|
|
datetime.datetime(2020, 4, 12, 0, 0)
|
|
|
|
>>> gauss_easter(2021)
|
|
datetime.datetime(2021, 4, 4, 0, 0)
|
|
"""
|
|
metonic_cycle = year % 19
|
|
julian_leap_year = year % 4
|
|
non_leap_year = year % 7
|
|
leap_day_inhibits = math.floor(year / 100)
|
|
lunar_orbit_correction = math.floor((13 + 8 * leap_day_inhibits) / 25)
|
|
leap_day_reinstall_number = leap_day_inhibits / 4
|
|
secular_moon_shift = (
|
|
15 - lunar_orbit_correction + leap_day_inhibits - leap_day_reinstall_number
|
|
) % 30
|
|
century_starting_point = (4 + leap_day_inhibits - leap_day_reinstall_number) % 7
|
|
|
|
# days to be added to March 21
|
|
days_to_add = (19 * metonic_cycle + secular_moon_shift) % 30
|
|
|
|
# PHM -> Paschal Full Moon
|
|
days_from_phm_to_sunday = (
|
|
2 * julian_leap_year
|
|
+ 4 * non_leap_year
|
|
+ 6 * days_to_add
|
|
+ century_starting_point
|
|
) % 7
|
|
|
|
if days_to_add == 29 and days_from_phm_to_sunday == 6:
|
|
return datetime(year, 4, 19)
|
|
elif days_to_add == 28 and days_from_phm_to_sunday == 6:
|
|
return datetime(year, 4, 18)
|
|
else:
|
|
return datetime(year, 3, 22) + timedelta(
|
|
days=int(days_to_add + days_from_phm_to_sunday)
|
|
)
|
|
|
|
|
|
if __name__ == "__main__":
|
|
for year in (1994, 2000, 2010, 2021, 2023):
|
|
tense = "will be" if year > datetime.now().year else "was"
|
|
print(f"Easter in {year} {tense} {gauss_easter(year)}")
|