gistfile1.py

months = [ 31, 0, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 ]

def is_leap_year(year):
    if (year % 4):
        return 0
    elif (year % 100):
        return 1
    elif (year % 400):
        return 0
    else:
        return 1

def last_day_of_month(year, month):
    if (month == 2):
        if (is_leap_year(year)):
            return 29
        else:
            return 28

    return months[ month - 1 ]

data = [ [1900, 2], [2000, 2], [2009, 8], [2009, 9] ]
for data in data:
    print str(data[0]) + "/" + str(data[1]) + " -> " + str(last_day_of_month(data[0], data[1]))