Add 2020 - Day 4 - Part 1

.idea/runConfigurations/2020___Day_04.xml

@@ -0,0 +1,18 @@
+<component name="ProjectRunConfigurationManager">
+  <configuration default="false" name="2020 - Day 04" type="CargoCommandRunConfiguration" factoryName="Cargo Command">
+    <option name="command" value="run --bin 04" />
+    <option name="workingDirectory" value="file://$PROJECT_DIR$/2020/04" />
+    <option name="channel" value="DEFAULT" />
+    <option name="requiredFeatures" value="true" />
+    <option name="allFeatures" value="false" />
+    <option name="emulateTerminal" value="false" />
+    <option name="withSudo" value="false" />
+    <option name="backtrace" value="SHORT" />
+    <envs />
+    <option name="isRedirectInput" value="false" />
+    <option name="redirectInputPath" value="" />
+    <method v="2">
+      <option name="CARGO.BUILD_TASK_PROVIDER" enabled="true" />
+    </method>
+  </configuration>
+</component>

2020/04/main.rs

@@ -0,0 +1,101 @@
+use std::collections::{HashMap, HashSet};
+use std::error::Error;
+
+use lazy_static::lazy_static;
+
+use crate::utils::GenericError;
+
+#[path = "../utils/mod.rs"]
+mod utils;
+
+fn main() -> Result<(), Box<dyn Error>> {
+	let lines = utils::read_input_lines()?;
+	let passports = load_passports(&lines)?;
+	
+	let valid_passports = passports.iter().filter(|p| p.is_valid_or_from_north_pole()).count();
+	println!("Valid passports: {}", valid_passports);
+	
+	Ok(())
+}
+
+fn load_passports(lines: &Vec<String>) -> Result<Vec<Passport>, GenericError> {
+	let mut passports = Vec::new();
+	let mut passport = Passport::new();
+	
+	for line in lines {
+		if line.is_empty() {
+			passports.push(passport);
+			passport = Passport::new();
+		} else {
+			passport.load_fields_from_line(line.as_str())?;
+		}
+	}
+	
+	passports.push(passport);
+	Ok(passports)
+}
+
+#[derive(Eq, PartialEq, Hash, Debug, Copy, Clone)]
+enum PassportField {
+	BirthYear,
+	IssueYear,
+	ExpirationYear,
+	Height,
+	HairColor,
+	EyeColor,
+	PassportId,
+	CountryId,
+}
+
+impl PassportField {
+	fn from(s: &str) -> Option<PassportField> {
+		match s {
+			"byr" => Some(PassportField::BirthYear),
+			"iyr" => Some(PassportField::IssueYear),
+			"eyr" => Some(PassportField::ExpirationYear),
+			"hgt" => Some(PassportField::Height),
+			"hcl" => Some(PassportField::HairColor),
+			"ecl" => Some(PassportField::EyeColor),
+			"pid" => Some(PassportField::PassportId),
+			"cid" => Some(PassportField::CountryId),
+			_ => None
+		}
+	}
+}
+
+struct Passport {
+	fields: HashMap<PassportField, String>,
+}
+
+lazy_static! {
+	static ref REQUIRED_FIELDS: HashSet<PassportField> = HashSet::from([
+		PassportField::BirthYear,
+		PassportField::IssueYear,
+		PassportField::ExpirationYear,
+		PassportField::Height,
+		PassportField::HairColor,
+		PassportField::EyeColor,
+		PassportField::PassportId
+	]);
+}
+
+impl Passport {
+	fn new() -> Passport {
+		Passport { fields: HashMap::new() }
+	}
+	
+	fn load_fields_from_line(&mut self, line: &str) -> Result<(), GenericError> {
+		for field_entry in line.split(' ') {
+			let (field_name, field_value) = field_entry.split_once(':').ok_or_else(|| GenericError::new("Passport entry is missing a colon."))?;
+			let field = PassportField::from(field_name).ok_or_else(|| GenericError::new(format!("Passport field is invalid: {}", field_name)))?;
+			self.fields.insert(field, field_value.to_string());
+		}
+		
+		Ok(())
+	}
+	
+	fn is_valid_or_from_north_pole(&self) -> bool {
+		let fields = &self.fields.keys().map(|f| *f).collect::<HashSet<PassportField>>();
+		return fields.is_superset(&REQUIRED_FIELDS);
+	}
+}

2020/Cargo.lock

@@ -5,3 +5,12 @@ version = 3
 [[package]]
 name = "chylex-aoc-2020"
 version = "0.1.0"
+dependencies = [
+ "lazy_static",
+]
+
+[[package]]
+name = "lazy_static"
+version = "1.4.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e2abad23fbc42b3700f2f279844dc832adb2b2eb069b2df918f455c4e18cc646"

2020/Cargo.toml

@@ -3,6 +3,9 @@ name = "chylex-aoc-2020"
 version = "0.1.0"
 edition = "2021"
 
+[dependencies]
+lazy_static = "1.4.0"
+
 [[bin]]
 name = "01"
 path = "01/main.rs"
@@ -14,3 +17,7 @@ path = "02/main.rs"
 [[bin]]
 name = "03"
 path = "03/main.rs"
+
+[[bin]]
+name = "04"
+path = "04/main.rs"

2020/utils/mod.rs

@@ -10,6 +10,7 @@ pub fn read_input_lines() -> Result<Vec<String>, io::Error> {
 	return BufReader::new(file).lines().collect();
 }
 
+#[allow(dead_code)]
 pub fn parse_input_lines<T : FromStr>() -> Result<Vec<T>, Box<dyn Error>> where <T as FromStr>::Err : Into<Box<dyn Error>> {
 	return read_input_lines()?.iter().map(|line| line.parse::<T>()).collect::<Result<Vec<T>, T::Err>>().map_err(Into::into);
 }

README.md

@@ -40,6 +40,7 @@ The versions should not matter, but I used Visual Studio 2019 with `MSVC v142 (1
 | 2020 |  01 | Rust     |
 | 2020 |  02 | Rust     |
 | 2020 |  03 | Rust     |
+| 2020 |  04 | Rust     |
 | 2021 |  01 | Kotlin   |
 | 2021 |  02 | Kotlin   |
 | 2021 |  03 | Kotlin   |