day-01 part-1

2024/day-01/Cargo.toml

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+[package]
+name = "day-01"
+version = "0.1.0"
+edition = "2021"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]
+color-eyre.workspace = true

2024/day-01/src/bin/part1.rs

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+use color_eyre::Result;
+use day_01::part1::process;
+
+fn main() -> Result<()> {
+    let file = include_str!("../../input1.txt");
+    let result = process(file)?;
+    println!("{}", result);
+    Ok(())
+}

2024/day-01/src/bin/part2.rs

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+use color_eyre::Result;
+use day_01::part2::process;
+
+fn main() -> Result<()> {
+    let file = include_str!("../../input2.txt");
+    let result = process(file)?;
+    println!("{}", result);
+    Ok(())
+}

2024/day-01/src/lib.rs

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+pub mod part1;
+pub mod part2;

2024/day-01/src/part1.rs

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+use color_eyre::Result;
+
+pub fn process(input: &str) -> Result<usize> {
+    let (mut firsts, mut lasts): (Vec<_>, Vec<_>) = input
+        .lines()
+        .filter(|line| !line.is_empty())
+        .map(|line| {
+            let nums = line
+                .split_whitespace()
+                .map(|num| num.parse::<usize>().unwrap())
+                .collect::<Vec<_>>();
+            (*nums.first().unwrap(), *nums.last().unwrap())
+        })
+        .unzip();
+
+    firsts.sort();
+    lasts.sort();
+
+    let sum = firsts
+        .iter()
+        .zip(lasts.iter())
+        .map(|(first, last)| first.abs_diff(*last))
+        .sum();
+    Ok(sum)
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_process() -> Result<()> {
+        let input = "
+3   4
+4   3
+2   5
+1   3
+3   9
+3   3
+";
+        let result = 11;
+        assert_eq!(process(input)?, result);
+        Ok(())
+    }
+}

2024/day-01/src/part2.rs

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+use color_eyre::Result;
+
+pub fn process(input: &str) -> Result<usize> {
+    todo!("day xx - part 2");
+    Ok(0)
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_process() -> Result<()> {
+        let input = "";
+        todo!("haven't built test yet");
+        assert_eq!(0, process(input)?);
+        Ok(())
+    }
+}