day 1 done, no winnow

.gitignore

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+target/
+*/input

.rustfmt.toml

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+imports_granularity = "Crate"
+group_imports = "StdExternalCrate"
+wrap_comments = true
+edition = "2024"

Cargo.lock

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+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+version = 4
+
+[[package]]
+name = "day01"
+version = "0.1.0"
+dependencies = [
+ "winnow",
+]
+
+[[package]]
+name = "memchr"
+version = "2.7.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "78ca9ab1a0babb1e7d5695e3530886289c18cf2f87ec19a575a0abdce112e3a3"
+
+[[package]]
+name = "winnow"
+version = "0.6.20"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "36c1fec1a2bb5866f07c25f68c26e565c4c200aebb96d7e55710c19d3e8ac49b"
+dependencies = [
+ "memchr",
+]

Cargo.toml

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+[workspace]
+resolver = "2"
+members = ["day01"]
+
+[workspace.dependencies]
+winnow = "0.6"

day01/Cargo.toml

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+[package]
+name = "day01"
+version = "0.1.0"
+edition = "2024"
+
+[dependencies]
+winnow.workspace = true

day01/src/main.rs

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+use std::collections::HashMap;
+
+fn main() {
+    let input = std::fs::read_to_string("input").unwrap();
+    println!("{}", pt2(&input));
+}
+
+fn pt1(input: &str) -> i32 {
+    let (mut left, mut right) = parse_input(input);
+    left.sort_unstable();
+    right.sort_unstable();
+    left.iter()
+        .zip(right.iter())
+        .map(|(l, r)| (l - r).abs())
+        .sum()
+}
+
+fn pt2(input: &str) -> i32 {
+    let (left, right) = parse_input(input);
+    let mut rights = HashMap::new();
+    for num in &right {
+        *rights.entry(num).or_insert(0) += 1;
+    }
+
+    left.iter().map(|n| n * rights.get(n).unwrap_or(&0)).sum()
+}
+
+fn parse_input(input: &str) -> (Vec<i32>, Vec<i32>) {
+    let mut left = Vec::new();
+    let mut right = Vec::new();
+    for line in input.split("\n") {
+        let line: Vec<&str> = line
+            .split(|c: char| c.is_whitespace())
+            .filter(|c| !c.is_empty())
+            .collect();
+        if line.len() < 2 {
+            continue;
+        }
+        let l: i32 = line[0].parse().unwrap();
+        let r: i32 = line[1].parse().unwrap();
+        left.push(l);
+        right.push(r);
+    }
+    (left, right)
+}
+
+#[cfg(test)]
+mod test {
+    use super::*;
+    static P1_TEST: &str = "3   4
+4   3
+2   5
+1   3
+3   9
+3   3
+";
+
+    #[test]
+    fn test_p1() {
+        let val = pt1(P1_TEST);
+        assert_eq!(11, val);
+    }
+
+    #[test]
+    fn test_p2() {
+        let val = pt2(P1_TEST);
+        assert_eq!(31, val);
+    }
+}