Advent of Code - adventofcode.com

Day 4 was decent - I've been using FluentValidators a lot recently, so quite easy to use them here. Once you've got a passport object set up, you can write rules it's got to fulfil to be valid such as:

public class PassportDataValidator : AbstractValidator<PassportData>
        {
            public PassportDataValidator()
            {
                RuleFor(passport => passport.byr).InclusiveBetween(1920, 2002);
                RuleFor(passport => passport.iyr).InclusiveBetween(2010, 2020);
            }
    }