aoc2/aoc2025/day1.rs
2025-12-01 13:36:43 +01:00

57 lines
1.3 KiB
Rust

use utils::load_string;
const TEST_INPUT: &str =
"L68
L30
R48
L5
R60
L55
L1
L99
R14
L82";
const START: u32 = 50;
enum Rotation {
Left(u32),
Right(u32),
}
fn parse(input: &str) -> Vec<Rotation> {
input.lines().map(|l| {
let (indicator, number) = l.split_at(1);
match indicator {
"L" => Rotation::Left(number.parse().unwrap()),
"R" => Rotation::Right(number.parse().unwrap()),
_ => panic!("hey!")
}
}).collect()
}
pub fn part1() -> u32 {
let input = &load_string("inputs/2025/day1.input");
//let input = TEST_INPUT;
let mut current_rotation = START;
let mut result: u32 = 0;
for roation in parse(input).iter() {
match roation {
Rotation::Left(amount) => {
// overflows to the left
current_rotation = (((current_rotation as i32) - *amount as i32).rem_euclid(100)) as u32;
},
Rotation::Right(amount) => {
// overflows to the right
current_rotation = (((current_rotation as i32) + *amount as i32).rem_euclid(100)) as u32;
},
}
if current_rotation == 0 {
result += 1;
}
}
result
}
pub fn part2() -> u32 {
0
}