aoc/year2016/
day08.rs

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1//! # Two-Factor Authentication
2//!
3//! The pixels are sparse enough that's it efficient to store them as [`Point`] objects and
4//! manipulate individually. Pixels don't overlap so we can use a vec instead of a set to store
5//! distinct points without overcounting.
6//!
7//! [`Point`]: crate::util::point
8use crate::util::iter::*;
9use crate::util::parse::*;
10use crate::util::point::*;
11
12pub fn parse(input: &str) -> Vec<Point> {
13    let amounts = input.iter_signed::<i32>().chunk::<2>();
14    let mut points = Vec::new();
15
16    for (line, [a, b]) in input.lines().zip(amounts) {
17        if line.starts_with("rect") {
18            for x in 0..a {
19                for y in 0..b {
20                    points.push(Point::new(x, y));
21                }
22            }
23        } else if line.starts_with("rotate row") {
24            for point in &mut points {
25                if point.y == a {
26                    point.x = (point.x + b) % 50;
27                }
28            }
29        } else {
30            for point in &mut points {
31                if point.x == a {
32                    point.y = (point.y + b) % 6;
33                }
34            }
35        }
36    }
37
38    points
39}
40
41pub fn part1(input: &[Point]) -> usize {
42    input.len()
43}
44
45pub fn part2(input: &[Point]) -> String {
46    let width = input.iter().map(|p| p.x).max().unwrap() + 1;
47
48    let mut pixels = vec!['.'; width as usize * 6];
49    for point in input {
50        pixels[(width * point.y + point.x) as usize] = '#';
51    }
52
53    let mut result = pixels
54        .chunks_exact(width as usize)
55        .map(|row| row.iter().collect())
56        .collect::<Vec<String>>()
57        .join("\n");
58    result.insert(0, '\n');
59    result
60}
aoc/year2016/day08.rs

aoc/year2016/
day08.rs
