3 Commits

Author SHA1 Message Date
Stefan Bühler 8c30eb1099 day1: add examples as unit tests 2 years ago
Stefan Bühler 17a271e24e day1: change to iterator style 2 years ago
Stefan Bühler 45a381165b add workspace in root folder 2 years ago
  1. 0
      .gitignore
  2. 6
      Cargo.lock
  3. 4
      Cargo.toml
  4. 59
      day1/src/main.rs

0
day1/.gitignore → .gitignore

6
Cargo.lock

@ -0,0 +1,6 @@
# This file is automatically @generated by Cargo.
# It is not intended for manual editing.
[[package]]
name = "day1"
version = "0.1.0"

4
Cargo.toml

@ -0,0 +1,4 @@
[workspace]
members = [
"day1",
]

59
day1/src/main.rs

@ -1,10 +1,12 @@
fn fuel_for_modules1(input: &str) -> i64 {
let mut fuel: i64 = 0;
for module in input.split_whitespace() {
let module: i64 = module.parse().unwrap();
fuel += (module / 3) - 2;
}
fuel
fn fuel_for_mass1(mass: u64) -> u64 {
mass / 3 - 2
}
fn fuel_for_modules1<I>(input: I) -> u64
where
I: IntoIterator<Item = u64>,
{
input.into_iter().map(fuel_for_mass1).sum()
}
fn fuel_for_mass2(mass: u64) -> u64 {
@ -13,17 +15,42 @@ fn fuel_for_mass2(mass: u64) -> u64 {
fuel + fuel_for_mass2(fuel)
}
fn fuel_for_modules2(input: &str) -> u64 {
let mut fuel: u64 = 0;
for module in input.split_whitespace() {
let module: u64 = module.parse().unwrap();
fuel += fuel_for_mass2(module);
}
fuel
fn fuel_for_modules2<I>(input: I) -> u64
where
I: IntoIterator<Item = u64>,
{
input.into_iter().map(fuel_for_mass2).sum()
}
fn main() {
let input = include_str!("input.txt");
println!("Fuel 1: {}", fuel_for_modules1(input));
let input = include_str!("input.txt").split_whitespace().map(|s| s.parse::<u64>().unwrap());
println!("Fuel 1: {}", fuel_for_modules1(input.clone()));
println!("Fuel 2: {}", fuel_for_modules2(input));
}
#[cfg(test)]
mod day1test {
#[test]
fn example1() {
// Original descriptions:
// > For a mass of 12, divide by 3 and round down to get 4, then subtract 2 to get 2.
// > For a mass of 14, dividing by 3 and rounding down still yields 4, so the fuel required is also 2.
// > For a mass of 1969, the fuel required is 654.
// > For a mass of 100756, the fuel required is 33583.
assert_eq!(super::fuel_for_mass1(12), 2);
assert_eq!(super::fuel_for_mass1(14), 2);
assert_eq!(super::fuel_for_mass1(1969), 654);
assert_eq!(super::fuel_for_mass1(100756), 33583);
}
#[test]
fn example2() {
// Original descriptions:
// > A module of mass 14 requires 2 fuel. This fuel requires no further fuel (2 divided by 3 and rounded down is 0, which would call for a negative fuel), so the total fuel required is still just 2.
// > At first, a module of mass 1969 requires 654 fuel. Then, this fuel requires 216 more fuel (654 / 3 - 2). 216 then requires 70 more fuel, which requires 21 fuel, which requires 5 fuel, which requires no further fuel. So, the total fuel required for a module of mass 1969 is 654 + 216 + 70 + 21 + 5 = 966.
// > The fuel required by a module of mass 100756 and its fuel is: 33583 + 11192 + 3728 + 1240 + 411 + 135 + 43 + 12 + 2 = 50346.
assert_eq!(super::fuel_for_mass2(14), 2);
assert_eq!(super::fuel_for_mass2(1969), 966);
assert_eq!(super::fuel_for_mass2(100756), 50346);
}
}
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