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//! # Day 4: Passport Processing
//!
//! You arrive at the airport only to realize that you grabbed your North Pole Credentials instead
//! of your passport. While these documents are extremely similar, North Pole Credentials aren't
//! issued by a country and therefore aren't actually valid documentation for travel in most of the
//! world.
//!
//! It seems like you're not the only one having problems, though; a very long line has formed for
//! the automatic passport scanners, and the delay could upset your travel itinerary.
//!
//! Due to some questionable network security, you realize you might be able to solve both of these
//! problems at the same time.
//!
//! The automatic passport scanners are slow because they're having trouble **detecting which
//! passports have all required fields**. The expected fields are as follows:
//!
//! - `byr` (Birth Year)
//! - `iyr` (Issue Year)
//! - `eyr` (Expiration Year)
//! - `hgt` (Height)
//! - `hcl` (Hair Color)
//! - `ecl` (Eye Color)
//! - `pid` (Passport ID)
//! - `cid` (Country ID)
//!
//! Passport data is validated in batch files (your puzzle input). Each passport is represented as a
//! sequence of `key:value` pairs separated by spaces or newlines. Passports are separated by blank
//! lines.
//!
//! Here is an example batch file containing four passports:
//!
//! ```txt
//! ecl:gry pid:860033327 eyr:2020 hcl:#fffffd
//! byr:1937 iyr:2017 cid:147 hgt:183cm
//!
//! iyr:2013 ecl:amb cid:350 eyr:2023 pid:028048884
//! hcl:#cfa07d byr:1929
//!
//! hcl:#ae17e1 iyr:2013
//! eyr:2024
//! ecl:brn pid:760753108 byr:1931
//! hgt:179cm
//!
//! hcl:#cfa07d eyr:2025 pid:166559648
//! iyr:2011 ecl:brn hgt:59in
//! ```
//!
//! The first passport is **valid** - all eight fields are present. The second passport is
//! **invalid** - it is missing `hgt` (the Height field).
//!
//! The third passport is interesting; the **only missing field** is `cid`, so it looks like data
//! from North Pole Credentials, not a passport at all! Surely, nobody would mind if you made the
//! system temporarily ignore missing `cid` fields. Treat this "passport" as **valid**.
//!
//! The fourth passport is missing two fields, `cid` and `byr`. Missing `cid` is fine, but missing
//! any other field is not, so this passport is **invalid**.
//!
//! According to the above rules, your improved system would report **`2`** valid passports.
//!
//! Count the number of **valid** passports - those that have all required fields. Treat `cid` as
//! optional. **In your batch file, how many passports are valid?**
//!
//! ## Part Two
//!
//! The line is moving more quickly now, but you overhear airport security talking about how
//! passports with invalid data are getting through. Better add some data validation, quick!
//!
//! You can continue to ignore the `cid` field, but each other field has strict rules about what
//! values are valid for automatic validation:
//!
//! - `byr` (Birth Year) - four digits; at least `1920` and at most `2002`.
//! - `iyr` (Issue Year) - four digits; at least `2010` and at most `2020`.
//! - `eyr` (Expiration Year) - four digits; at least `2020` and at most `2030`.
//! - `hgt` (Height) - a number followed by either `cm` or `in`:
//! - If `cm`, the number must be at least `150` and at most `193`.
//! - If `in`, the number must be at least `59` and at most `76`.
//! - `hcl` (Hair Color) - a `#` followed by exactly six characters `0`-`9` or `a`-`f`.
//! - `ecl` (Eye Color) - exactly one of: `amb` `blu` `brn` `gry` `grn` `hzl` `oth`.
//! - `pid` (Passport ID) - a nine-digit number, including leading zeroes.
//! - `cid` (Country ID) - ignored, missing or not.
//!
//! Your job is to count the passports where all required fields are both **present** and **valid**
//! according to the above rules. Here are some example values:
//!
//! ```txt
//! byr valid: 2002
//! byr invalid: 2003
//!
//! hgt valid: 60in
//! hgt valid: 190cm
//! hgt invalid: 190in
//! hgt invalid: 190
//!
//! hcl valid: #123abc
//! hcl invalid: #123abz
//! hcl invalid: 123abc
//!
//! ecl valid: brn
//! ecl invalid: wat
//!
//! pid valid: 000000001
//! pid invalid: 0123456789
//! ```
//!
//! Here are some invalid passports:
//!
//! ```txt
//! 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
//! ```
//!
//! Here are some valid passports:
//!
//! ```txt
//! 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
//! ```
//!
//! Count the number of **valid** passports - those that have all required fields **and valid
//! values**. Continue to treat `cid` as optional. **In your batch file, how many passports are
//! valid?**
use std::collections::HashMap;
use anyhow::{Context, Result};
pub const INPUT: &str = include_str!("d04.txt");
pub fn solve_part_one(input: &str) -> Result<usize> {
Ok(parse_input(input)?
.into_iter()
.filter(|p| {
["byr", "iyr", "eyr", "hgt", "hcl", "ecl", "pid"].iter().all(|f| p.contains_key(f))
})
.count())
}
pub fn solve_part_two(input: &str) -> Result<usize> {
Ok(parse_input(input)?
.into_iter()
.filter(|p| {
let byr = p
.get("byr")
.and_then(|v| v.parse::<u16>().ok())
.filter(|v| (1920..=2002).contains(v))
.is_some();
let iyr = p
.get("iyr")
.and_then(|v| v.parse::<u16>().ok())
.filter(|v| (2010..=2020).contains(v))
.is_some();
let eyr = p
.get("eyr")
.and_then(|v| v.parse::<u16>().ok())
.filter(|v| (2020..=2030).contains(v))
.is_some();
let hgt = p
.get("hgt")
.filter(|v| v.len() > 2)
.and_then(|v| v[..v.len() - 2].parse::<u8>().ok().map(|h| (h, &v[v.len() - 2..])))
.filter(|(h, s)| match *s {
"cm" => 150 <= *h && *h <= 193,
"in" => 59 <= *h && *h <= 76,
_ => false,
})
.is_some();
let hcl = p
.get("hcl")
.filter(|v| {
v.len() == 7
&& v.chars().next().map(|c| c == '#').unwrap_or_default()
&& v.chars().skip(1).all(|c| matches!(c, '0'..='9' | 'a'..='f'))
})
.is_some();
let ecl = p
.get("ecl")
.filter(|v| ["amb", "blu", "brn", "gry", "grn", "hzl", "oth"].contains(v))
.is_some();
let pid = p
.get("pid")
.filter(|v| v.len() == 9 && v.chars().all(|c| c.is_ascii_digit()))
.is_some();
byr && iyr && eyr && hgt && hcl && ecl && pid
})
.count())
}
fn parse_input(input: &str) -> Result<Vec<HashMap<&str, &str>>> {
input
.split_terminator("\n\n")
.map(|pp| {
pp.split_terminator(|c| c == ' ' || c == '\n')
.map(|e| {
let mut parts = e.splitn(2, ':');
let k = parts.next().context("key missing")?;
let v = parts.next().context("value missing")?;
Ok((k, v))
})
.collect::<Result<HashMap<_, _>>>()
})
.collect()
}
#[cfg(test)]
mod tests {
use indoc::indoc;
use super::*;
#[test]
fn part_one() {
let input = indoc! {"
ecl:gry pid:860033327 eyr:2020 hcl:#fffffd
byr:1937 iyr:2017 cid:147 hgt:183cm
iyr:2013 ecl:amb cid:350 eyr:2023 pid:028048884
hcl:#cfa07d byr:1929
hcl:#ae17e1 iyr:2013
eyr:2024
ecl:brn pid:760753108 byr:1931
hgt:179cm
hcl:#cfa07d eyr:2025 pid:166559648
iyr:2011 ecl:brn hgt:59in
"};
assert_eq!(2, solve_part_one(input).unwrap());
}
#[test]
fn part_two() {
let input = indoc! {"
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
"};
assert_eq!(0, solve_part_two(input).unwrap());
let input = indoc! {"
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
"};
assert_eq!(4, solve_part_two(input).unwrap());
}
}