2019 day 1 part 1

2019/Cargo.lock

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+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+[[package]]
+name = "advent-of-code"
+version = "0.1.0"
+

2019/Cargo.toml

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+[package]
+name = "advent-of-code"
+version = "0.1.0"
+authors = ["Wesley Moore <wes@wezm.net>"]
+edition = "2018"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]

2019/input/day1.txt

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+90903
+135889
+120859
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+56532
+92489
+87979
+149620
+137436
+62999
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+79131
+64907
+95570
+132347
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+128180
+113508
+70342
+139386
+131234
+140377
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+52090
+62615
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+138512
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+94578
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+116731
+123488
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+129242
+51587
+149536
+71096
+110104
+145155
+139278
+78799
+62410
+64645
+112849
+60402

2019/src/bin/day1.rs

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+use std::io;
+
+use advent_of_code::input;
+
+fn main() -> io::Result<()> {
+    // Specifically, to find the fuel required for a module, take its mass, divide by three, round down, and subtract 2.
+    let result: i32 = input::read_number_list("input/day1.txt")?
+        .into_iter()
+        .map(|module_mass| (module_mass as f64 / 3.).floor() as i32 - 2)
+        .sum();
+
+    println!("Result: {}", result);
+
+    Ok(())
+}

2019/src/input.rs

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+use std::fs::File;
+use std::io;
+use std::io::{BufRead, BufReader};
+use std::path::Path;
+
+pub fn read_number_list<P: AsRef<Path>>(path: P) -> io::Result<Vec<i32>> {
+    let input = BufReader::new(File::open(path)?);
+    let mut output = Vec::new();
+
+    for line in input.lines() {
+        let line = line?;
+        output.push(
+            line.parse()
+                .map_err(|err| io::Error::new(io::ErrorKind::InvalidInput, err))?,
+        )
+    }
+
+    Ok(output)
+}

2019/src/lib.rs

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+pub mod input;