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use std::fs;
use std::path::Path;
enum Cmd {
Forward(i32),
Depth(i32)
}
impl From<&str> for Cmd {
fn from(s: &str) -> Self {
let (cmd, amount) = s.split_once(' ').expect("Malformed input");
let amount = amount.parse().expect("Malformed input");
match cmd {
"down" => Cmd::Depth(amount),
"up" => Cmd::Depth(-amount),
"forward" => Cmd::Forward(amount),
_ => unreachable!("Malformed input")
}
}
}
fn ex1(route: &[Cmd]) {
let pos = route.iter().fold((0,0),
|(f,d),c| match c {
Cmd::Depth(a) => (f,d+a),
Cmd::Forward(a) => (f+a,d),
}
);
println!("Ex1: The result is {}", pos.0 * pos.1);
}
fn ex2(route: &[Cmd]) {
let pos = route.iter().fold((0,0,0),
|(a,f,d),c| match c {
Cmd::Depth(i) => (a+i,f,d),
Cmd::Forward(i) => (a,f+i,d+a*i),
}
);
println!("Ex2: The result is {}", pos.1 * pos.2);
}
/* AOC21 Day 2: https://adventofcode.com/2021/day/2 */
fn main() {
let input = Path::new("resources").join("input.txt");
let content = fs::read_to_string(input).expect("Unable to read input file");
let route: Vec<Cmd> = content.lines().map( |l| Cmd::from(l)).collect();
ex1(&route);
ex2(&route);
}
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