You are given the following information, but you may prefer to do some research for yourself.
以下信息仅供参考(你可能会想自己去百度)：
1 Jan 1900 was a Monday. 1900年一月一号是星期一
Thirty days has September, 九月、四月、六月以及十一月有30天
April, June and November.
All the rest have thirty-one, 其他月份有31天
Saving February alone, 二月份比较特殊
Which has twenty-eight, rain or shine. 闰年29天，平年28天
And on leap years, twenty-nine.
A leap year occurs on any year evenly divisible by 4, but not on a century unless it is divisible by 400.
闰年指可以被4整除的年份，但如果是世纪(如：1900)的话，需要能够整除400才算闰年
How many Sundays fell on the first of the month during the twentieth century (1 Jan 1901 to 31 Dec 2000)?
二十世纪有多少个星期天在月份的第一天(从1900-01-01到2000-12-31)？
def leep_year(year): if year % 100 == 0: # century if year % 400 == 0: return True else: if year % 4 == 0: return True return False week = [‘Monday‘, ‘Tuesday‘, ‘Wednesday‘, ‘Thursday‘, ‘Friday‘, ‘Saturday‘, ‘Sunday‘] month = {‘January‘: 31, ‘February‘: 28, ‘March‘: 31, ‘April‘: 30, ‘May‘: 31, ‘June‘: 30, ‘July‘: 31, ‘August‘: 31, ‘September‘: 30, ‘October‘: 31, ‘November‘: 30, ‘December‘: 31} count = 0 day = ‘Monday‘ index = 0 for year in range(1900, 2001): if leep_year(year): month[‘February‘] = 29 else: month[‘February‘] = 28 for m, d in month.items(): if day == ‘Sunday‘: count += 1 index = week.index(day) + d % 7 if index >= 7: index %= 7 day = week[index] if year == 1900: count = 0 print(count)
原文：https://www.cnblogs.com/noonjuan/p/11028852.html