aoc/year2019/
day13.rs

1//! # Care Package
2//!
3//! Keeps track of the `x` position of both the ball and paddle then uses the [`signum`] function
4//! to provide input to the joystick that tracks the ball.
5//!
6//! Just for fun this solution will play an animated game in the console if
7//! "--features frivolity" is enabled.
8//!
9//! [`signum`]: i64::signum
10use super::intcode::*;
11use crate::util::parse::*;
12
13pub fn parse(input: &str) -> Vec<i64> {
14    input.iter_signed().collect()
15}
16
17pub fn part1(input: &[i64]) -> usize {
18    let mut computer = Computer::new(input);
19    let mut blocks = 0;
20
21    while let [_, _, State::Output(t)] = [computer.run(), computer.run(), computer.run()] {
22        if t == 2 {
23            blocks += 1;
24        }
25    }
26
27    blocks
28}
29
30pub fn part2(input: &[i64]) -> i64 {
31    let mut modified = input.to_vec();
32    modified[0] = 2;
33
34    let mut computer = Computer::new(&modified);
35    let mut tiles = Vec::with_capacity(1_000);
36    let mut stride = 0;
37    let mut score = 0;
38    let mut blocks = score;
39    let mut ball: i64 = 0;
40    let mut paddle: i64 = 0;
41
42    loop {
43        let x = match computer.run() {
44            State::Input => {
45                // Always track the ball.
46                let delta = (ball - paddle).signum();
47                computer.input(delta);
48                continue;
49            }
50            State::Output(x) => x,
51            State::Halted => unreachable!(),
52        };
53        let State::Output(y) = computer.run() else { unreachable!() };
54        let State::Output(t) = computer.run() else { unreachable!() };
55
56        if x < 0 {
57            score = t;
58            if blocks == 0 {
59                break score;
60            }
61        } else {
62            if x >= stride {
63                stride = x + 1;
64            }
65            let index = (stride * y + x) as usize;
66            if index >= tiles.len() {
67                tiles.resize(index + 1, 0);
68            }
69
70            match t {
71                0 if tiles[index] == 2 => blocks -= 1,
72                2 if tiles[index] != 2 => blocks += 1,
73                3 => paddle = x,
74                4 => ball = x,
75                _ => (),
76            }
77
78            tiles[index] = t;
79        }
80
81        // Non-essential but hilarious. Enable feature then run program in a command line
82        // console to observe an animated game of breakout.
83        #[cfg(feature = "frivolity")]
84        draw(&tiles, stride, score, blocks);
85    }
86}
87
88#[cfg(feature = "frivolity")]
89fn draw(tiles: &[i64], stride: i64, score: i64, blocks: i64) {
90    use crate::util::ansi::*;
91    use std::fmt::Write as _;
92    use std::thread::sleep;
93    use std::time::Duration;
94
95    // Wait until the initial screen is complete.
96    let paddle = tiles.iter().rposition(|&t| t == 3).unwrap_or(tiles.len());
97    if tiles[paddle..].iter().filter(|&&t| t == 1).count() < 3 {
98        return;
99    }
100
101    let s = &mut String::new();
102    let _ = writeln!(s, "{WHITE}{BOLD}Blocks: {blocks}\tScore: {score} {RESET}");
103    let mut y = 0;
104
105    while stride * y < tiles.len() as i64 {
106        for x in 0..stride {
107            let index = (stride * y + x) as usize;
108            let _unused = match tiles[index] {
109                0 => write!(s, " "),
110                1 if y == 0 => write!(s, "{GREEN}_{RESET}"),
111                1 => write!(s, "{GREEN}|{RESET}"),
112                2 => write!(s, "{BLUE}#{RESET}"),
113                3 => write!(s, "{WHITE}{BOLD}={RESET}"),
114                4 => write!(s, "{YELLOW}{BOLD}o{RESET}"),
115                _ => unreachable!(),
116            };
117        }
118        s.push('\n');
119        y += 1;
120    }
121
122    println!("{HOME}{CLEAR}{s}");
123    sleep(Duration::from_millis(20));
124}
aoc/year2019/day13.rs

aoc/year2019/
day13.rs
