my solutions to advent of code
aylac.top
aoc
advent-of-code
1use std::mem::swap;
2
3#[inline]
4fn get_at(world: &Vec<Vec<bool>>, size: usize, x: isize, y: isize) -> u8 {
5 let isize = size as isize;
6 if x == isize || x == -1 || y == isize || y == -1 {
7 return 0;
8 };
9 if *world
10 .get(y as usize)
11 .expect("invalid position")
12 .get(x as usize)
13 .expect("invalid position")
14 {
15 1
16 } else {
17 0
18 }
19}
20
21#[inline]
22fn get_at_bool(world: &Vec<Vec<bool>>, x: usize, y: usize) -> bool {
23 *world
24 .get(y)
25 .expect("invalid position")
26 .get(x)
27 .expect("invalid position")
28}
29
30fn generations(times: u32, mut world: Vec<Vec<bool>>, size: usize, stuck: bool) -> Vec<Vec<bool>> {
31 let mut new_world = vec![vec![false; size]; size];
32 if stuck {
33 let sizem = size - 1;
34 world[0][0] = true;
35 world[0][sizem] = true;
36 world[sizem][0] = true;
37 world[sizem][sizem] = true;
38 }
39
40 for _ in 0..times {
41 for y in 0..size {
42 for x in 0..size {
43 let xo = x as isize;
44 let yo = y as isize;
45 let xm = xo - 1;
46 let ym = yo - 1;
47 let xp = xo + 1;
48 let yp = yo + 1;
49
50 let was = get_at_bool(&world, x, y);
51 let neighbours = get_at(&world, size, xm, ym)
52 + get_at(&world, size, xo, ym)
53 + get_at(&world, size, xp, ym)
54 + get_at(&world, size, xm, yo)
55 + get_at(&world, size, xp, yo)
56 + get_at(&world, size, xm, yp)
57 + get_at(&world, size, xo, yp)
58 + get_at(&world, size, xp, yp);
59 new_world[y][x] = neighbours == 3 || (neighbours == 2 && was);
60 }
61 }
62
63 swap(&mut world, &mut new_world);
64
65 // i hate the duplication here :(
66 if stuck {
67 let sizem = size - 1;
68 world[0][0] = true;
69 world[0][sizem] = true;
70 world[sizem][0] = true;
71 world[sizem][sizem] = true;
72 }
73 }
74 world
75}
76
77fn main() {
78 let input = include_str!("../../input.txt").trim();
79 let size = input.split_once("\n").expect("invalid input").0.len();
80 let input: Vec<Vec<bool>> = input
81 .split("\n")
82 .map(|line| line.chars().map(|v| v == '#').collect())
83 .collect();
84
85 let part_1 = generations(100, input.clone(), size, false)
86 .iter()
87 .flatten()
88 .filter(|v| **v)
89 .count();
90 println!("Part 1: {}", part_1);
91
92 let part_2 = generations(100, input.clone(), size, true)
93 .iter()
94 .flatten()
95 .filter(|v| **v)
96 .count();
97 println!("Part 2: {}", part_2);
98}