2019: day01: part 1

Cargo.lock

@@ -4,3 +4,7 @@
 name = "aoc2018"
 version = "0.1.0"
 
+[[package]]
+name = "aoc2019"
+version = "0.1.0"
+

Cargo.toml

@@ -1,4 +1,5 @@
 [workspace]
 members = [
     "aoc2018",
+    "aoc2019",
 ]

aoc2019/Cargo.toml

@@ -0,0 +1,9 @@
+[package]
+name = "aoc2019"
+version = "0.1.0"
+authors = ["Antoine Martin <antoine97.martin@gmail.com>"]
+edition = "2018"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]

aoc2019/input/day01.txt

@@ -0,0 +1,100 @@
+102111
+81442
+104967
+146349
+97956
+148336
+55752
+110518
+136080
+79361
+101709
+71796
+72543
+88058
+87187
+67778
+75471
+135632
+101309
+67060
+87048
+64775
+52160
+119184
+55284
+83289
+94809
+78017
+117854
+76469
+94504
+92372
+133595
+107269
+57182
+85578
+83777
+91167
+86119
+114263
+60369
+72562
+69544
+92699
+135045
+147230
+83105
+143488
+56494
+63019
+112366
+128119
+58293
+132542
+93266
+76032
+111651
+127490
+107633
+61260
+120876
+116254
+101151
+128722
+111623
+103470
+53224
+93922
+87624
+131864
+82431
+90465
+148373
+90119
+123744
+118713
+143700
+113581
+140687
+119516
+149497
+72281
+108641
+111605
+148274
+69326
+116571
+56540
+87595
+55068
+120602
+56557
+125534
+133162
+51828
+117883
+94637
+54577
+135114
+83866

aoc2019/src/day01.rs

@@ -0,0 +1,42 @@
+use super::Result;
+
+const INPUT: &str = include_str!("../input/day01.txt");
+
+pub fn run() -> Result<()> {
+    println!("part 1: {}", part1(INPUT)?);
+
+    Ok(())
+}
+
+fn fuel_needed(module_weight: u64) -> u64 {
+    (module_weight / 3) - 2
+}
+
+fn part1(input: &str) -> Result<u64> {
+    input
+        .lines()
+        .map(|line| line.parse::<u64>())
+        .map(|w| match w {
+            Ok(w) => Ok(fuel_needed(w)),
+            Err(e) => Err(Box::from(e)),
+        })
+        .sum()
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn part1_provided() {
+        assert_eq!(fuel_needed(12), 2);
+        assert_eq!(fuel_needed(14), 2);
+        assert_eq!(fuel_needed(1969), 654);
+        assert_eq!(fuel_needed(100756), 33583);
+    }
+
+    #[test]
+    fn part1_real() {
+        assert_eq!(part1(INPUT).unwrap(), 3268951);
+    }
+}

aoc2019/src/lib.rs

@@ -0,0 +1,8 @@
+pub mod day01;
+
+pub type Result<T> = std::result::Result<T, Box<dyn std::error::Error>>;
+
+#[macro_export]
+macro_rules! err {
+    ($($string:expr),+) => (Box::<dyn Error>::from(format!($($string),+)))
+}

aoc2019/src/main.rs

@@ -0,0 +1,29 @@
+use std::env;
+
+use aoc2019::day01;
+
+use aoc2019::Result;
+
+fn main() -> Result<()> {
+    let days: &[fn() -> Result<()>] = &[day01::run];
+
+    let mut args = env::args();
+    args.next();
+
+    match args.next() {
+        Some(arg) => {
+            let day: usize = arg.parse().expect("Please provide a day number");
+            days[day - 1]().expect("error running day specified");
+        }
+        None => {
+            for (i, day) in days.iter().enumerate() {
+                let i = i + 1;
+                println!("day{}: ", i);
+                day().unwrap_or_else(|e| panic!("error running day {}: {}", i, e));
+                println!();
+            }
+        }
+    }
+
+    Ok(())
+}