aoc2020/day4/part2/main.d

module day4.part2.main;

import std;

void main()
{
    readText("input").parsePassports.countValidPassports.writeln;
}

alias Passport = string[string];

auto parsePassports(string input)
{
    return input.splitter("\n\n").map!(passport => passport.splitter().map!((entry) {
            auto keyAndValue = entry.split(':');
            return tuple(keyAndValue[0], keyAndValue[1]);
        }).assocArray);
}

bool isValidHeight(string hgt)
{
    auto match = hgt.matchFirst(r"^(\d+)(cm|in)$");
    if (!match || match.length != 3)
        return false;

    auto number = match[1].to!int;
    switch (match[2])
    {
    case "cm":
        return number >= 150 && number <= 193;
        break;
    case "in":
        return number >= 59 && number <= 76;
    default:
        return false;
    }
}

alias isBetween = (x, min, max) => x >= min && x <= max;

bool isValidPassport(Passport passport)
{
    // dfmt off
    auto validators = [
        "byr" : s => s.length == 4 && s.all!isDigit && s.to!int.isBetween(1920, 2002),
        "iyr" : s => s.length == 4 && s.all!isDigit && s.to!int.isBetween(2010, 2020),
        "eyr" : s => s.length == 4 && s.all!isDigit && s.to!int.isBetween(2020, 2030),
        "hgt" : &isValidHeight,
        "hcl" : s => s.matchFirst(r"^#[0-9a-f]{6}$").to!bool,
        "ecl" : s => [ "amb", "blu", "brn", "gry", "grn", "hzl", "oth" ].canFind(s),
        "pid" : s => s.matchFirst(r"^\d{9}$").to!bool
    ];
    // dfmt on

    return validators.byKeyValue.all!(validator => validator.key in passport
            && validator.value()(passport[validator.key]));
}

auto countValidPassports(R)(R r) if (isInputRange!R && is(ElementType!R == Passport))
{
    return r.filter!isValidPassport.count;
}

unittest
{
    auto input = `eyr:1972 cid:100
hcl:#18171d ecl:amb hgt:170 pid:186cm iyr:2018 byr:1926

iyr:2019
hcl:#602927 eyr:1967 hgt:170cm
ecl:grn pid:012533040 byr:1946

hcl:dab227 iyr:2012
ecl:brn hgt:182cm pid:021572410 eyr:2020 byr:1992 cid:277

hgt:59cm ecl:zzz
eyr:2038 hcl:74454a iyr:2023
pid:3556412378 byr:2007`;

    auto passPorts = input.parsePassports;
    assert(passPorts.countValidPassports == 0);
}

unittest
{
    auto input = `pid:087499704 hgt:74in ecl:grn iyr:2012 eyr:2030 byr:1980
hcl:#623a2f

eyr:2029 ecl:blu cid:129 byr:1989
iyr:2014 pid:896056539 hcl:#a97842 hgt:165cm

hcl:#888785
hgt:164cm byr:2001 iyr:2015 cid:88
pid:545766238 ecl:hzl
eyr:2022

iyr:2010 hgt:158cm hcl:#b6652a ecl:blu byr:1944 eyr:2021 pid:093154719`;

    auto passPorts = input.parsePassports;
    assert(passPorts.countValidPassports == 4);
}