day16 started

src/common/file.rs

@@ -9,9 +9,9 @@ pub fn read_lines(day_num: usize, file: &str) -> io::Result<Vec<String>> {
     Ok(fs::read_to_string(format_path(day_num, file))?
         .split('\n')
         .with_position()
-        .filter_map(|line| match line {
-            (itertools::Position::Last, line) if line.is_empty() => None,
-            (_, line) => Some(line.to_string()),
+        .filter_map(|(pos, line)| match pos {
+            itertools::Position::Last if line.is_empty() => None,
+            _ => Some(line.to_owned()),
         })
         .collect())
 }

src/days/day16/mod.rs

@@ -1,4 +1,10 @@
+use std::num::ParseIntError;
+
 use super::template::{DayTrait, ResultType};
+use const_format::concatcp;
+use once_cell::sync::Lazy;
+use regex::Regex;
+use thiserror::Error;
 
 const DAY_NUMBER: usize = 16;
 
@@ -9,15 +15,114 @@ impl DayTrait for Day {
         DAY_NUMBER
     }
 
-    fn part1(&self, _lines: &[String]) -> anyhow::Result<ResultType> {
+    fn part1(&self, lines: &[String]) -> anyhow::Result<ResultType> {
         Ok(ResultType::Nothing)
     }
 
-    fn part2(&self, _lines: &[String]) -> anyhow::Result<ResultType> {
+    fn part2(&self, lines: &[String]) -> anyhow::Result<ResultType> {
         Ok(ResultType::Nothing)
     }
 }
 
+#[derive(Debug, Error)]
+enum ValveError {
+    #[error("Not an Integer")]
+    NotAnInt(#[from] ParseIntError),
+
+    #[error("Not a valid valve: {0}")]
+    NotAValidValve(String),
+}
+
+const ID: &str = "[[:alpha:]]+";
+const COMMON: &str = concatcp!("^Valve (?<id>", ID, r") has flow rate=(?<rate>\d+); ");
+const PLURAL_STR: &str = concatcp!(
+    COMMON,
+    "tunnels lead to valves (?<exits>",
+    ID,
+    "(?:, ",
+    ID,
+    ")+)$"
+);
+const SINGULAR_STR: &str = concatcp!(COMMON, "tunnel leads to valve (?<exits>", ID, ")$");
+
+#[derive(Debug, PartialEq, Eq, PartialOrd, Ord)]
+struct Valve {
+    id: String,
+    rate: i64,
+    distances: Vec<(String, i64)>,
+}
+
+impl Valve {
+    fn from_regex(regex: &Regex, line: &str) -> Option<Result<Valve, ValveError>> {
+        regex.captures(line).map(|caps| {
+            match (caps.name("id"), caps.name("rate"), caps.name("exits")) {
+                (Some(id), Some(rate), Some(exits)) => {
+                    let rate = rate.as_str().parse()?;
+                    let distances = exits
+                        .as_str()
+                        .split(",")
+                        .map(|s| (s.trim_start().to_string(), 1))
+                        .collect();
+                    Ok(Valve {
+                        id: id.as_str().to_string(),
+                        rate,
+                        distances,
+                    })
+                }
+                _ => Err(ValveError::NotAValidValve(line.to_string())),
+            }
+        })
+    }
+
+    pub fn known_distances(&self) -> usize {
+        self.distances.len() + 1
+    }
+
+    pub fn steps_to(&self, to: &str) -> Option<i64> {
+        self.distances
+            .iter()
+            .find_map(|(other, distance)| if other == to { Some(*distance) } else { None })
+            .or_else(|| (to == self.id).then_some(0))
+    }
+}
+
+impl TryFrom<&str> for Valve {
+    type Error = ValveError;
+
+    fn try_from(value: &str) -> Result<Valve, Self::Error> {
+        static PLURAL: Lazy<Regex> = Lazy::new(|| Regex::new(PLURAL_STR).unwrap());
+        static SINGULAR: Lazy<Regex> = Lazy::new(|| Regex::new(SINGULAR_STR).unwrap());
+        Valve::from_regex(&PLURAL, value)
+            .or_else(|| Valve::from_regex(&SINGULAR, value))
+            .unwrap_or_else(|| Err(ValveError::NotAValidValve(value.to_string())))
+    }
+}
+
+struct System {
+    valves: Vec<Valve>,
+}
+
+impl System {
+    pub fn get_valve(&self, id: &str) -> Option<&Valve> {
+        self.valves.iter().find(|valve| valve.id == id)
+    }
+
+    pub fn len(&self) -> usize {
+        self.valves.len()
+    }
+}
+
+impl System {
+    fn build(lines: &[String]) -> Result<System, ValveError> {
+        Ok(System {
+            valves: lines
+                .iter()
+                .map(|line| Valve::try_from(line.as_str()))
+                .collect::<Result<Vec<_>, _>>()?,
+        })
+    }
+}
+
 #[cfg(test)]
 mod test {
     use super::*;
@@ -45,4 +150,32 @@ mod test {
 
         Ok(())
     }
+
+    #[test]
+    fn parse_plural() -> Result<()> {
+        let line = "Valve BB has flow rate=13; tunnels lead to valves CC, AA";
+        let expected = Valve {
+            id: "BB".to_string(),
+            rate: 13,
+            distances: vec![("CC".to_string(), 1), ("AA".to_string(), 1)],
+        };
+        let result = Valve::try_from(line)?;
+        assert_eq!(expected, result);
+
+        Ok(())
+    }
+
+    #[test]
+    fn parse_singular() -> Result<()> {
+        let line = "Valve HH has flow rate=22; tunnel leads to valve GG";
+        let expected = Valve {
+            id: "HH".to_string(),
+            rate: 22,
+            distances: vec![("GG".to_string(), 1)],
+        };
+        let result = Valve::try_from(line)?;
+        assert_eq!(expected, result);
+
+        Ok(())
+    }
 }