07.rs

use std::time::Instant;
use itertools::Itertools;
use intcoder::{IntCoder, ExitCode};

const PROGRAM: [i64; 523] = [3,8,1001,8,10,8,105,1,0,0,21,42,67,84,97,118,199,280,361,442,99999,3,9,101,4,9,9,102,5,9,9,101,2,9,9,1002,9,2,9,4,9,99,3,9,101,5,9,9,102,5,9,9,1001,9,5,9,102,3,9,9,1001,9,2,9,4,9,99,3,9,1001,9,5,9,1002,9,2,9,1001,9,5,9,4,9,99,3,9,1001,9,5,9,1002,9,3,9,4,9,99,3,9,102,4,9,9,101,4,9,9,102,2,9,9,101,3,9,9,4,9,99,3,9,102,2,9,9,4,9,3,9,1002,9,2,9,4,9,3,9,1001,9,2,9,4,9,3,9,102,2,9,9,4,9,3,9,102,2,9,9,4,9,3,9,1001,9,2,9,4,9,3,9,1002,9,2,9,4,9,3,9,102,2,9,9,4,9,3,9,1001,9,2,9,4,9,3,9,101,2,9,9,4,9,99,3,9,1001,9,1,9,4,9,3,9,101,2,9,9,4,9,3,9,1001,9,2,9,4,9,3,9,1002,9,2,9,4,9,3,9,101,2,9,9,4,9,3,9,1002,9,2,9,4,9,3,9,102,2,9,9,4,9,3,9,1002,9,2,9,4,9,3,9,101,1,9,9,4,9,3,9,101,2,9,9,4,9,99,3,9,101,1,9,9,4,9,3,9,1001,9,1,9,4,9,3,9,1002,9,2,9,4,9,3,9,1002,9,2,9,4,9,3,9,1002,9,2,9,4,9,3,9,1001,9,2,9,4,9,3,9,102,2,9,9,4,9,3,9,102,2,9,9,4,9,3,9,101,2,9,9,4,9,3,9,1001,9,2,9,4,9,99,3,9,102,2,9,9,4,9,3,9,102,2,9,9,4,9,3,9,1001,9,2,9,4,9,3,9,102,2,9,9,4,9,3,9,1001,9,2,9,4,9,3,9,102,2,9,9,4,9,3,9,102,2,9,9,4,9,3,9,101,1,9,9,4,9,3,9,1001,9,2,9,4,9,3,9,1002,9,2,9,4,9,99,3,9,101,1,9,9,4,9,3,9,101,1,9,9,4,9,3,9,102,2,9,9,4,9,3,9,1001,9,2,9,4,9,3,9,1001,9,2,9,4,9,3,9,1002,9,2,9,4,9,3,9,101,1,9,9,4,9,3,9,102,2,9,9,4,9,3,9,1001,9,1,9,4,9,3,9,1001,9,2,9,4,9,99];

fn part_one() -> i64 {
  [0,1,2,3,4].iter()
    .permutations(5)
    .map(|digits| digits.iter()
      .fold(0, |prev, &&i| {
        let mut cpu = IntCoder::new(&PROGRAM);
        cpu.push_input(i);
        cpu.push_input(prev);
        cpu.execute_until_output()
      })
    )
    .max()
    .unwrap()
}

fn part_two() -> i64 {
  [5,6,7,8,9].iter()
    .permutations(5)
    .map(|digits| {
      let mut cpus = vec![IntCoder::new(&PROGRAM); 5];
      for i in 0..5 { cpus[i].push_input(*digits[i]); }
      let mut input = 0;
      for i in (0..5).cycle() {
        cpus[i].push_input(input);
        match cpus[i].execute() {
          ExitCode::Output(o)  => input = o,
          ExitCode::Halted     => return input,
          ExitCode::AwaitInput => unreachable!(),
        }
      }
      unreachable!()
    })
    .max()
    .unwrap()
}

fn main() {
  let now = Instant::now();
  println!("Part one: {}", part_one());
  println!("Part two: {}", part_two());
  println!("Time: {}ms", now.elapsed().as_millis());
}