Initial commit

day1/rust/Cargo.toml

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+[package]
+name = "day1"
+version = "0.1.0"
+authors = ["Tobias Eidelpes <tobias@eidelpes.info>"]
+edition = "2018"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]

day1/rust/src/main.rs

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+use std::fs::File;
+use std::env;
+use std::io::{Error, BufRead, BufReader};
+
+fn main() -> Result<(), Error> {
+    let args: Vec<String> = env::args().collect();
+
+    let filename = &args[1];
+
+    let reader = BufReader::new(File::open(filename).unwrap());
+
+    let mut result: i64 = 0;
+
+    for line in reader.lines() {
+        let n = line.unwrap().parse::<i64>().unwrap();
+        result += calculate_fuel(n);
+    }
+    println!("Result: {}", result);
+
+    Ok(())
+}
+
+fn calculate_fuel(mass: i64) -> i64 {
+    let fuel = mass / 3 - 2;
+    if fuel < 0 {
+        return 0;
+    } else {
+        return (fuel) + calculate_fuel(fuel);
+    }
+}