day03 finished

src/days/day03/mod.rs

@@ -0,0 +1,144 @@
+use itertools::Itertools;
+use thiserror::Error;
+
+use super::template::{DayTrait, ResultType};
+
+const DAY_NUMBER: usize = 3;
+
+pub struct Day;
+
+impl DayTrait for Day {
+    fn get_day_number(&self) -> usize {
+        DAY_NUMBER
+    }
+
+    fn part1(&self, lines: &str) -> anyhow::Result<ResultType> {
+        let sum = lines
+            .split('\n')
+            .map(|rucksack| find_double(rucksack).and_then(priority))
+            .collect::<Result<Vec<_>, _>>()?
+            .iter()
+            .sum();
+        Ok(ResultType::IntResult(sum))
+    }
+
+    fn part2(&self, lines: &str) -> anyhow::Result<ResultType> {
+        let sum = lines
+            .split('\n')
+            .chunks(3)
+            .into_iter()
+            .map(|chunk| find_badge(&chunk.collect::<Vec<_>>()).and_then(priority))
+            .collect::<Result<Vec<_>, _>>()?
+            .iter()
+            .sum();
+        Ok(ResultType::IntResult(sum))
+    }
+}
+
+#[derive(Debug, Error)]
+enum RucksackError {
+    #[error("No double item found")]
+    NoDoubleFound,
+
+    #[error("Not a valid char: {0}")]
+    InvalidChar(char),
+
+    #[error("Need at least two elves for common item")]
+    NeedAtLeastTwo,
+
+    #[error("No common badge was found")]
+    NoBadgeFound,
+}
+
+fn priority(c: char) -> Result<i64, RucksackError> {
+    match c {
+        'a'..='z' => Ok(c as i64 - 'a' as i64 + 1),
+        'A'..='Z' => Ok(c as i64 - 'A' as i64 + 27),
+        _ => Err(RucksackError::InvalidChar(c)),
+    }
+}
+
+fn find_double(content: &str) -> Result<char, RucksackError> {
+    let length = content.len() / 2;
+    let part1 = &content[..length];
+    let part2 = &content[length..];
+
+    for c in part1.chars() {
+        if part2.contains(c) {
+            return Ok(c);
+        }
+    }
+
+    Err(RucksackError::NoDoubleFound)?
+}
+
+fn find_badge<'a>(elves: &[&str]) -> Result<char, RucksackError> {
+    if elves.len() < 2 {
+        return Err(RucksackError::NeedAtLeastTwo);
+    };
+    for c in elves[0].chars() {
+        let mut found = true;
+        for other in &elves[1..] {
+            if !other.contains(c) {
+                found = false;
+            }
+        }
+        if found {
+            return Ok(c);
+        }
+    }
+    Err(RucksackError::NoBadgeFound)
+}
+
+#[cfg(test)]
+mod test {
+    use super::*;
+    use crate::common::file::read_data;
+    use anyhow::Result;
+
+    #[test]
+    fn test_rucksack() -> Result<(), RucksackError> {
+        let input = "vJrwpWtwJgWrhcsFMMfFFhFp";
+        let expected = 16;
+        let result = find_double(input).and_then(priority)?;
+        assert_eq!(result, expected);
+
+        Ok(())
+    }
+
+    #[test]
+    fn test_part1() -> Result<()> {
+        let day = Day {};
+        let lines = read_data(day.get_day_number(), "example01.txt")?;
+        let expected = ResultType::IntResult(157);
+        let result = day.part1(&lines)?;
+        assert_eq!(result, expected);
+
+        Ok(())
+    }
+
+    #[test]
+    fn test_find_badge() -> Result<(), RucksackError> {
+        let input = vec![
+            "vJrwpWtwJgWrhcsFMMfFFhFp",
+            "jqHRNqRjqzjGDLGLrsFMfFZSrLrFZsSL",
+            "PmmdzqPrVvPwwTWBwg",
+        ];
+        let expected = 18;
+        let result = find_badge(&input).and_then(priority)?;
+        assert_eq!(result, expected);
+
+        Ok(())
+    }
+
+    #[test]
+    fn test_part2() -> Result<()> {
+        let day = Day {};
+        let lines = read_data(day.get_day_number(), "example01.txt")?;
+        let expected = ResultType::IntResult(70);
+        let result = day.part2(&lines)?;
+        assert_eq!(result, expected);
+
+        Ok(())
+    }
+}