You are given the following information, but you may prefer to do some research for yourself. -1 Jan 1900 was a Monday. -Thirty days has September, April, June and November. All the rest have thirty-one, Saving February alone, Which has twenty-eight, rain or shine. 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. How many Sundays fell on the first of the month during the twentieth century (1 Jan 1901 to 31 Dec 2000)? Run this solution at repl.io here.
#First thing to check is what day of the week is 1 Jan 1901
monthnum = {1: 31, 2: 28, 3: 31, 4: 30, 5: 31, 6: 30, 7: 31, 8: 31, 9: 30, 10: 31, 11: 30, 12: 31}
monthnumleap = {1: 31, 2: 29, 3: 31, 4: 30, 5: 31, 6: 30, 7: 31, 8: 31, 9: 30, 10: 31, 11: 30, 12: 31}
#-----Inital date --------
#First weekday of 1 Jan 1901 is a Tuesday
weekday = 2
#days then return to 1
day = 1
#12 months then return to 1
month = 1 #use monthnum[datemonth] to return number of days (N.B. leap)
#count forever
year = 1901
#date format
date = (day, month, year)
initial_date = date
#-------------------------
#Target date
finalday = 31
finalmonth = 12
finalyear = 2000
finaldate = (finalday, finalmonth, finalyear)
count = 0
while finaldate != date:
if month == 12 and day == 31:
year += 1
month = 1
day = 0
elif year % 4 == 0 and year % 100 != 0 and year % 400 != 0 and monthnumleap[month] == day:
month += 1
day = 0
elif monthnum[month] == day:
month += 1
day = 0
if weekday == 7:
weekday = 0
day += 1
weekday += 1
date = (day, month, year)
if day == 1 and weekday == 7:
count += 1
print("Number of Sundays on the 1st of each month between " \
+ str(initial_date) + " and " + str(date) + " is: " \
+ str(count))