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use std::io::{self, Read};
#[derive(Debug, Clone, Copy)]
struct Hex(i32, i32, i32);
impl Hex {
fn mov(self, dir: &str) -> Self {
let Hex(x, y, z) = self;
match dir {
"n" => Hex(x, y + 1, z - 1),
"ne" => Hex(x + 1, y, z - 1),
"se" => Hex(x + 1, y - 1, z),
"s" => Hex(x, y - 1, z + 1),
"sw" => Hex(x - 1, y, z + 1),
"nw" => Hex(x - 1, y + 1, z),
_ => unimplemented!(),
}
}
}
fn solve1(input: &str) -> i32 {
let mut hex = Hex(0, 0, 0);
for dir in input.split(',') {
hex = hex.mov(dir);
}
(hex.0.abs() + hex.1.abs() + hex.2.abs()) / 2
}
fn main() {
let mut input = String::new();
io::stdin().read_to_string(&mut input).unwrap();
println!("Part 1: {}", solve1(input.trim()));
}
#[test]
fn part1() {
assert_eq!(3, solve1("ne,ne,ne"));
assert_eq!(0, solve1("ne,ne,sw,sw"));
assert_eq!(2, solve1("ne,ne,s,s"));
assert_eq!(3, solve1("se,sw,se,sw,sw"));
}
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