day02 solved

src/day02/mod.rs

@@ -0,0 +1,172 @@
+use std::{fmt::Display, str::FromStr};
+
+use color_eyre::{
+    Result,
+    eyre::{Error, OptionExt, eyre},
+};
+use itertools::Itertools;
+use tracing::{debug, debug_span, info, info_span, instrument};
+
+pub const INPUT: &str = include_str!("input/input.txt");
+
+#[derive(Clone, Debug)]
+struct ProductRange(std::ops::RangeInclusive<i64>);
+
+impl FromStr for ProductRange {
+    type Err = Error;
+
+    fn from_str(s: &str) -> Result<Self, Self::Err> {
+        let mut parts = s.split('-');
+        let start = parts
+            .next()
+            .ok_or(eyre!("Invalid product range: no start"))?
+            .parse::<i64>()?;
+        let end = parts
+            .next()
+            .ok_or(eyre!("Invalid product range: no end"))?
+            .parse::<i64>()?;
+        if parts.next().is_some() {
+            return Err(eyre!("Invalid product range: too many parts"));
+        }
+        Ok(ProductRange(start..=end))
+    }
+}
+
+impl Display for ProductRange {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        write!(f, "{}-{}", self.0.start(), self.0.end())
+    }
+}
+
+impl Iterator for ProductRange {
+    type Item = i64;
+
+    fn next(&mut self) -> Option<Self::Item> {
+        self.0.next()
+    }
+
+    fn size_hint(&self) -> (usize, Option<usize>) {
+        self.0.size_hint()
+    }
+}
+
+fn is_valid_product_id(id: i64) -> Result<bool> {
+    let digits: Vec<u32> = id
+        .to_string()
+        .chars()
+        .map(|c| {
+            c.to_digit(10)
+                .ok_or_eyre("Invalid product id: contains a non-decimal digit")
+        })
+        .collect::<Result<Vec<u32>>>()?;
+    if digits.len() % 2 != 0 {
+        return Ok(true);
+    }
+    Ok(digits[..digits.len() / 2] != digits[digits.len() / 2..])
+}
+
+fn is_valid_product_id2(id: i64) -> Result<bool> {
+    let digits: Vec<u32> = id
+        .to_string()
+        .chars()
+        .map(|c| {
+            c.to_digit(10)
+                .ok_or_eyre("Invalid product id: contains a non-decimal digit")
+        })
+        .collect::<Result<Vec<u32>>>()?;
+    let mut chunk_size = digits.len() / 2;
+    loop {
+        if chunk_size == 0 {
+            break;
+        }
+        if digits
+            .chunks(chunk_size)
+            .tuple_windows()
+            .all(|(a, b)| a == b)
+        {
+            return Ok(false);
+        }
+        chunk_size -= 1;
+    }
+    Ok(true)
+}
+
+impl ProductRange {
+    fn invalid_ids(self) -> Result<Vec<i64>> {
+        let mut invalid_ids = vec![];
+
+        for id in self {
+            if !is_valid_product_id(id)? {
+                invalid_ids.push(id);
+            }
+        }
+
+        debug!("Invalid IDs: {:?}", &invalid_ids);
+        Ok(invalid_ids)
+    }
+
+    fn invalid_ids2(self) -> Result<Vec<i64>> {
+        let mut invalid_ids = vec![];
+
+        for id in self {
+            if !is_valid_product_id2(id)? {
+                invalid_ids.push(id);
+            }
+        }
+
+        debug!("Invalid IDs: {:?}", &invalid_ids);
+        Ok(invalid_ids)
+    }
+}
+
+#[instrument(skip(input))]
+pub fn part1(input: &str) -> Result<i64> {
+    let mut total_invalid = 0;
+    for range in input.trim().split(',') {
+        let _span = debug_span!("range", range = %range).entered();
+        let range: ProductRange = range.parse()?;
+        total_invalid += range.invalid_ids()?.iter().sum::<i64>();
+    }
+    Ok(total_invalid)
+}
+
+#[instrument(skip(input))]
+pub fn part2(input: &str) -> Result<i64> {
+    let mut total_invalid = 0;
+    for range in input.trim().split(',') {
+        let _span = debug_span!("range", range = %range).entered();
+        let range: ProductRange = range.parse()?;
+        total_invalid += range.invalid_ids2()?.iter().sum::<i64>();
+    }
+    Ok(total_invalid)
+}
+
+pub fn solve() -> Result<()> {
+    info!("Day 2");
+    {
+        let _span = info_span!("day02").entered();
+        let p1 = part1(INPUT)?;
+        info!("Part 1: {}", p1);
+        let p2 = part2(INPUT)?;
+        info!("Part 2: {}", p2);
+    }
+    Ok(())
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use test_log::test;
+
+    const TEST_INPUT1: &str = include_str!("input/test1.txt");
+
+    #[test]
+    fn test_part1() {
+        assert_eq!(part1(TEST_INPUT1).unwrap(), 1227775554);
+    }
+
+    #[test]
+    fn test_part2() {
+        assert_eq!(part2(TEST_INPUT1).unwrap(), 4174379265);
+    }
+}