Add Rust day 1

Cargo.toml

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+[package]
+name = "aoc-2024"
+version = "0.1.0"
+edition = "2021"
+
+[dependencies]

src/day_01/mod.rs

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+pub mod part_1;
+pub mod part_2;

src/day_01/part_1.rs

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+use crate::utils;
+
+pub fn answer(lines : &str) -> u32 {
+    let ( mut left, mut right ) : ( Vec<u32>, Vec<u32> ) = lines
+        .split("\n")
+        .filter_map(parse_line)
+        .unzip();
+    
+    left.sort_unstable();
+    right.sort_unstable();
+    
+    left.iter()
+        .zip(right.iter())
+        .map(|(x, y)| abs_diff(&x, &y))
+        .sum()
+}
+
+fn abs_diff(l : &u32, r : &u32) -> u32 {
+    if l >= r { l - r } else { r - l }
+}
+
+fn parse_line(s : &str) -> Option<( u32, u32 )> {
+    let (left, right) = s.trim().split_once("   ")?;
+
+    Some(( utils::str_to_u32(left)?, utils::str_to_u32(right)? ))
+}

src/day_01/part_2.rs

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+use crate::utils;
+
+pub fn answer(s : &str) -> u32 {
+    let ( left, right ) : ( Vec<u32>, Vec<u32> ) = s
+        .split("\n")
+        .filter_map(parse_line)
+        .unzip();
+    
+    left.iter()
+        .map(|x| right.iter().filter(|y| x == *y).count() as u32 * x)
+        .sum()
+}
+
+fn parse_line(s : &str) -> Option<( u32, u32 )> {
+    let (left, right) = s.trim().split_once("   ")?;
+
+    Some(( utils::str_to_u32(left)?, utils::str_to_u32(right)? ))
+}

src/lib.rs

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+mod utils;
+mod day_01;
+
+pub fn day_01() {
+    let s : String = utils::read_from_file("inputs/01.txt");
+    println!("Day 01 part 1: {}", day_01::part_1::answer(s.as_str()));
+    println!("Day 01 part 2: {}", day_01::part_2::answer(s.as_str()));
+}
+

src/main.rs

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+fn main() {
+    aoc_2024::day_01();
+}

src/utils/mod.rs

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+use std::fs;
+
+pub fn read_from_file(name : &str) -> String {
+    match fs::read_to_string(name) {
+        Err(error) => {
+            println!("Failed to read file {name}: {error}");
+            String::new()
+        },
+        Ok(s) => s,
+    }
+}
+
+pub fn str_to_u32(s : &str) -> Option<u32> {
+    s.trim().to_string().parse::<u32>().ok()
+}