19 lines
410 B
Python

weekday = [5]
month = (31, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30)
def leap_day(year):
if not (year % 400):
return 1
if (year % 100) and (not (year % 4)):
return 1
return 0
for y in range(1900, 2001):
for m in month:
weekday.append((weekday[-1] + m) % 7)
if 28 == m:
weekday[-1] = (weekday[-1] + leap_day(y)) % 7
print(weekday[13:].count(0))