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|
use aoc2019::*;
use rpds::list;
use rpds::list::List;
use rpds::rbt_set;
use rpds::set::red_black_tree_set::RedBlackTreeSet;
use rpds::vector;
use rpds::vector::Vector;
use std::io;
use std::io::prelude::*;
use std::iter;
use std::process;
use structopt::StructOpt;
#[derive(Debug, StructOpt)]
#[structopt(name = "Day 15: Oxygen System")]
/// Executes an Intcode robot that's searching a map. Prints the
/// time taken for oxygen to propagate to the whole area.
///
/// See https://adventofcode.com/2019/day/15 for details.
struct Opt {
/// Run in 'find' mode, find the oxygen tank but don't see how long it takes the oxygen to propagate
#[structopt(short = "f")]
find: bool,
}
fn main() {
let stdin = io::stdin();
let opt = Opt::from_args();
let program: IntcodeProgram = stdin
.lock()
.split(b',')
.map(|x| exit_on_failed_assertion(x, "Error reading input"))
.map(|x| exit_on_failed_assertion(String::from_utf8(x), "Input was not valid UTF-8"))
.map(|x| exit_on_failed_assertion(x.trim().parse::<Intcode>(), "Invalid number"))
.collect::<IntcodeProgram>();
if opt.find {
println!("{}", shortest_distance(program));
} else {
println!("{}", max_depth_from_oxygen(program));
}
}
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);
}
}
}
fn shortest_distance(program: IntcodeProgram) -> usize {
iter::successors(
Some((
rbt_set![(0, 0)],
vector![((0, 0), program.run_to_termination_or_input())],
)),
|(visited, programs)| {
Some(next_depth_states(
visited.clone(),
next_program_states(programs, visited),
))
},
)
.enumerate()
.find(|(_i, (_visited, programs))| {
programs
.iter()
.any(|(_location, program)| program.output == vector![2.into()])
})
.unwrap()
.0
}
fn max_depth_from_oxygen(program: IntcodeProgram) -> usize {
max_depth(
iter::successors(
Some((
rbt_set![(0, 0)],
vector![((0, 0), program.run_to_termination_or_input())],
)),
|(visited, programs)| {
Some(next_depth_states(
visited.clone(),
next_program_states(programs, visited),
))
},
)
.find(|(_visited, programs)| {
programs
.iter()
.any(|(_location, program)| program.output == vector![2.into()])
})
.unwrap()
.1
.iter()
.find(|(_location, program)| program.output == vector![2.into()])
.cloned()
.unwrap()
.1,
)
}
fn max_depth(program: IntcodeProgram) -> usize {
iter::successors(
Some((
rbt_set![(0, 0)],
vector![((0, 0), program.run_to_termination_or_input())],
)),
|(visited, programs)| {
Some(next_depth_states(
visited.clone(),
next_program_states(programs, visited),
))
},
)
.take_while(|(_visited, programs)| programs.len() > 0)
.count()
- 1
}
fn inputs() -> [((i32, i32), Intcode); 4] {
[
((0, 1), Intcode::from(1)),
((0, -1), Intcode::from(2)),
((1, 0), Intcode::from(3)),
((-1, 0), Intcode::from(4)),
]
}
fn next_program_states(
programs: &Vector<((i32, i32), IntcodeProgram)>,
visited: &RedBlackTreeSet<(i32, i32)>,
) -> Vector<((i32, i32), IntcodeProgram)> {
let inputs = inputs();
programs
.iter()
.flat_map(|(location, program)| {
inputs.iter().map(move |(vec, input)| {
(
(location.0 + vec.0, location.1 + vec.1),
program
.with_cleared_output()
.with_input(list![input.clone()])
.run_to_termination_or_input(),
)
})
})
.filter(|(location, program)| {
!visited.contains(location) && program.output != vector![0.into()]
})
.collect()
}
fn next_depth_states(
previous_visited: RedBlackTreeSet<(i32, i32)>,
programs: Vector<((i32, i32), IntcodeProgram)>,
) -> (
RedBlackTreeSet<(i32, i32)>,
Vector<((i32, i32), IntcodeProgram)>,
) {
(
programs
.iter()
.fold(previous_visited, |acc, (next, _)| acc.insert(*next)),
dedup_locations(programs),
)
}
fn dedup_locations(
programs: Vector<((i32, i32), IntcodeProgram)>,
) -> Vector<((i32, i32), IntcodeProgram)> {
programs.iter().fold(Vector::new(), |acc, next| {
if acc.iter().any(|(loc, _)| *loc == next.0) {
acc
} else {
acc.push_back(next.clone())
}
})
}
|
