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use std::fmt;
use std::io;
use std::io::prelude::*;
use std::process;
use std::str::FromStr;
use structopt::StructOpt;
#[derive(Debug, StructOpt)]
#[structopt(name = "Day 6: Universal Orbit Map")]
/// Counts the total number of direct and indirect orbits between planets.
///
/// Input is read from stdin, one direct orbit per line, in the format
/// `A)B` (B is orbiting A).
///
/// See https://adventofcode.com/2019/day/6 for details.
struct Opt {}
fn main() {
let stdin = io::stdin();
let opt = Opt::from_args();
let orbits = stdin
.lock()
.lines()
.map(|x| exit_on_failed_assertion(x, "Error reading input"))
.map(|x| exit_on_failed_assertion(x.parse::<Orbit>(), "Input was not a valid orbit"));
println!("{}", count_orbits(orbits));
}
fn exit_on_failed_assertion<A, E: std::error::Error>(data: Result<A, E>, message: &str) -> A {
match data {
Ok(data) => data,
Err(e) => {
eprintln!("{}: {}", message, e);
process::exit(1);
}
}
}
#[derive(Debug)]
struct StrError {
str: String,
}
impl fmt::Display for StrError {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
write!(f, "{}", self.str)
}
}
impl std::error::Error for StrError {}
struct Orbit {
a: String,
b: String,
}
impl FromStr for Orbit {
type Err = StrError;
fn from_str(s: &str) -> Result<Self, StrError> {
match s.split(')').collect::<Vec<_>>()[..] {
[a, b] => Ok(Orbit {
a: a.to_string(),
b: b.to_string(),
}),
_ => Err(StrError {
str: format!("{} is not a valid orbit description", s),
}),
}
}
}
fn count_orbits(it: impl Iterator<Item = Orbit>) -> usize {
// TODO
0
}
|
