day6: [rust] completed

diff --git a/day6/Cargo.toml b/day6/Cargo.toml
new file mode 100644 (file)
index 0000000..06d4c25
--- /dev/null
+++ b/day6/Cargo.toml
@@ -0,0 +1,7 @@
+[package]
+name = "aoc2023-day6"
+version = "1.0.0"
+
+[dependencies]
+clap = { version="4.4.11", features=["derive"] }
+rayon = "1.8.0"

diff --git a/day6/src/main.rs b/day6/src/main.rs
new file mode 100644 (file)
index 0000000..e1e2d8d
--- /dev/null
+++ b/day6/src/main.rs
@@ -0,0 +1,81 @@
+extern crate clap;
+extern crate rayon;
+
+use std::error::Error;
+use std::fs::File;
+use std::io::{prelude::*, BufReader};
+
+use rayon::prelude::*;
+use clap::{Parser, ArgAction};
+
+/// Advent of Code 2023 day 6
+#[derive(Parser, Default, Debug)]
+struct Arguments {
+    /// specify the input file name
+    filename: String,
+    #[arg(short, long, action=ArgAction::SetTrue)]
+    /// enable debug output
+    debug: Option<bool>,
+}
+
+type Parsed = (Vec<i64>, Vec<i64>);
+
+fn parse_input(filename: &str) -> Parsed {
+    let input = File::open(filename).expect("file not found");
+    let buffered = BufReader::new(input);
+    let data: Vec<String> = buffered.lines().collect::<Result<_,_>>().unwrap();
+    (
+        data[0].strip_prefix("Time: ")
+            .unwrap()
+            .split_whitespace()
+            .map(|x| x.parse::<i64>().unwrap())
+            .collect::<Vec<i64>>(),
+        data[1].strip_prefix("Distance: ")
+            .unwrap()
+            .split_whitespace()
+            .map(|x| x.parse::<i64>().unwrap())
+            .collect::<Vec<i64>>(),
+    )
+}
+
+fn part1(input: &Parsed) -> i64 {
+    input.0.iter().zip(input.1.iter())
+        .map(|(&t, &d)| (1..t)
+            .into_par_iter()
+            .filter(|&x| x * (t - x) > d)
+        .count() as i64)
+    .product()
+}
+
+fn part2(filename: &str) -> i64 {
+    let handle = File::open(filename).expect("file not found");
+    let buffered = BufReader::new(handle);
+    let data: Vec<String> = buffered.lines().collect::<Result<_,_>>().unwrap();
+    let input = (
+        data[0].strip_prefix("Time: ")
+            .unwrap()
+            .split_whitespace()
+            .collect::<String>()
+            .parse()
+            .unwrap(),
+        data[1].strip_prefix("Distance: ")
+            .unwrap()
+            .split_whitespace()
+            .collect::<String>()
+            .parse()
+            .unwrap()
+    );
+    part1(&(vec![input.0], vec![input.1]))
+}
+
+fn main() -> Result<(), Box<dyn Error>> {
+    let args = Arguments::parse();
+    let input = parse_input(&args.filename);
+    if args.debug.is_some() {
+        println!("Time: {:?}, Distance: {:?}", input.0, input.1);
+    }
+    println!("part 1: {}", part1(&input));
+    println!("part 2: {}", part2(&args.filename));
+
+    Ok(())
+}