Doomsday method practice script

day_of_the_week_guesser.py

#
# Link to Numberphile video that explains the algorithm to calculate the day of the week in your head
# https://www.youtube.com/watch?v=z2x3SSBVGJU&t=64s
#
# In this script i'm using a different methid called the Zeller’s congruence
# https://en.wikipedia.org/wiki/Zeller%27s_congruence
#

import random

def is_leap_year(year):
    if (year % 400 == 0) and (year % 100 == 0):
        return True
    elif (year % 4 ==0) and (year % 100 != 0):
        return True
    else:
        return False

good_guesses = 0
for i in range(1, 1000):

    month = random.randint(1, 12)
    year_fst = random.randint(17, 22)
    year_scn = random.randint(0, 99)
    year = year_fst * 100 + year_scn

    if (month in [1, 3, 5, 7, 8, 10, 12]):
        day = random.randint(1,31)
    elif (month in [4, 6, 9, 11]):
        day = random.randint(1,30)
    elif (is_leap_year(year)):
        day = random.randint(1,29)
    else:
        day = random.randint(1,28)

    days = ["Sun", "Mon", "Tue", "Wed", "Thu", "Fri", "Sat"]

    month -= 2
    if month == -1:
        month = 12
    elif month == -2:
        month = 11


    F= day + (((13*month)-1)//5) +year_scn+ (year_scn//4) +(year_fst//4)-2*year_fst
    if month == 12:
        month = -1
    elif month == 11:
        month = -2
    month += 2


    res = int(F) % 7
    while True:
        guess = input(f"{day}:{month}:{year} is a? ")
        if guess.lower() in [day.lower() for day in days]:
            if guess.lower() == days[res].lower():
                print("OK")
                good_guesses += 1
            else:
                print(f"NAY it was a {days[res]}")
            print(f"Success rate of {(good_guesses/i)*100}% (good_guesses: {good_guesses}/ total_guesses: {i})")
            break
        else:
            print(f"Invalid input, the valid inputs are {days}")