Project Euler Problem 19

projectEulerProb19.py

#!/usr/bin/python

# return true if this year is a leap year
def checkLeap(inYear):
    if(year % 4 == 0):
        if (year % 100 == 0 and year % 400 != 0):
            return False
        else: 
            return True
    else: 
        return False


# current_day
day = 0
year = 1900
month = 1
monthDays = [31,28,31,30,31,30,31,31,30,31,30,31]
monthDaysLeap = [31,29,31,30,31,30,31,31,30,31,30,31]
monthNames = ["Jan","Feb","Mar","April","May","June","July","Aug","Sept","Oct","Nov","Dec"]
dayNames = ["Sunday","Monday","Tuesday","Wednesday","Thursday","Friday","Saturday","Sunday"]

leapyr = False

sundayMonths = 0

# year to start with
# use "cal 1 1901" to find day to start with
year = 1901
day = 2
while (year <= 2000):
    # start again in January
    month = 1
    leapYr = checkLeap(year)
    
    # set the monthDays array depending on if its a leap year
    if(leapYr == True):
        curDays = monthDaysLeap
    else: 
        curDays = monthDays

    while(month < 13):
        # DEBUG
        #monthStr = "First day of", monthNames[month-1], day, ",", year, "is a", dayNames[day]
        #print monthStr
        # add current day plus length of next month 
        # mod with 7 to get first day of month for this month 
        
        # increment what day next month is
        day = (day + curDays[month-1]) % 7
        # increment the month
        if (day == 0):
            print "Found a month that starts with a Sunday in ", month+1, year
            sundayMonths = sundayMonths + 1
        month = month + 1
        
    year = year + 1



print "Found a total of", sundayMonths