initial commit

day1/.gitignore

@@ -0,0 +1 @@
+/target

day1/Cargo.lock

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+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+version = 3
+
+[[package]]
+name = "aho-corasick"
+version = "1.1.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "8e60d3430d3a69478ad0993f19238d2df97c507009a52b3c10addcd7f6bcb916"
+dependencies = [
+ "memchr",
+]
+
+[[package]]
+name = "day1"
+version = "0.1.0"
+dependencies = [
+ "regex",
+]
+
+[[package]]
+name = "memchr"
+version = "2.7.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "78ca9ab1a0babb1e7d5695e3530886289c18cf2f87ec19a575a0abdce112e3a3"
+
+[[package]]
+name = "regex"
+version = "1.11.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "b544ef1b4eac5dc2db33ea63606ae9ffcfac26c1416a2806ae0bf5f56b201191"
+dependencies = [
+ "aho-corasick",
+ "memchr",
+ "regex-automata",
+ "regex-syntax",
+]
+
+[[package]]
+name = "regex-automata"
+version = "0.4.9"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "809e8dc61f6de73b46c85f4c96486310fe304c434cfa43669d7b40f711150908"
+dependencies = [
+ "aho-corasick",
+ "memchr",
+ "regex-syntax",
+]
+
+[[package]]
+name = "regex-syntax"
+version = "0.8.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "2b15c43186be67a4fd63bee50d0303afffcef381492ebe2c5d87f324e1b8815c"

day1/Cargo.toml

@@ -0,0 +1,7 @@
+[package]
+name = "day1"
+version = "0.1.0"
+edition = "2021"
+
+[dependencies]
+regex = "1.11.1"

day1/src/main.rs

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+use std::fs::File;
+use std::io::{self, BufRead};
+use std::path::Path;
+use regex::Regex;
+
+fn main() {
+    let mut numbers_a = Vec::new();
+    let mut numbers_b = Vec::new();
+    let re = Regex::new(r"([0-9]+)\s+([0-9]+)$").unwrap();
+    if let Ok(lines) = read_lines("input") {
+        for line in lines.flatten() {
+            let Some(caps) = re.captures(&line) else { return };
+            let a = &caps[1];
+            let b = &caps[2];
+            numbers_a.push(a.parse::<i32>().unwrap());
+            numbers_b.push(b.parse::<i32>().unwrap());
+        }
+    }
+
+    assert!(numbers_a.len() == numbers_b.len());
+
+    numbers_a.sort();
+    numbers_b.sort();
+
+    let mut total_distance:i32 = 0;
+    let mut similarity_score:i32 = 0;
+    for i in 0..numbers_a.len() {
+        let dist = (numbers_a[i] - numbers_b[i]).abs();
+        total_distance += dist;
+
+        let mut similarity:i32 = 0;
+        for b in numbers_b.iter() {
+            if numbers_a[i] == *b {
+                similarity += numbers_a[i];
+            }
+        }
+        similarity_score += similarity;
+    }
+
+    println!("The total distance is {}.", total_distance);
+    println!("The similarity score is {}.", similarity_score);
+}
+
+fn read_lines<P>(filename: P) -> io::Result<io::Lines<io::BufReader<File>>>
+where P: AsRef<Path>, {
+    let file = File::open(filename)?;
+    Ok(io::BufReader::new(file).lines())
+}