1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
|
use std::fs;
use std::path::Path;
use std::collections::HashSet;
/* AOC21 Day 13: https://adventofcode.com/2021/day/13 */
fn main() {
let input = Path::new("resources").join("input.txt");
let content = fs::read_to_string(input).expect("Unable to read input file");
let (points,instructions) = content.split_once("\n\n").expect("Malformed input");
let points: HashSet<(u32,u32)> = points.lines().map(|l| {
let (x,y) = l.split_once(',').expect("Malformed input");
(x.parse().unwrap(),y.parse().unwrap())
}).collect();
let instructions: Vec<(bool,u32)> = instructions.lines().map(|l| {
let (axis,idx) = l.split_whitespace()
.nth(2).expect("Malformed input")
.split_once('=').expect("Malformed input");
(axis=="x", idx.parse().unwrap())
}).collect();
ex1(points.clone(), instructions[0]);
ex2(points, &instructions);
}
fn ex1(points: HashSet<(u32,u32)>, instruction: (bool,u32)) {
println!("Ex1: The result is {}", fold(points, instruction).len());
}
fn ex2(points: HashSet<(u32,u32)>, instructions: &[(bool,u32)]) {
let code = instructions.iter().fold(points, |ps,i| fold(ps, *i));
let code = {
let x_max = 1 + code.iter().map(|(x,_)| *x).max().unwrap() as usize;
let y_max = 1 + code.iter().map(|(_,y)| *y).max().unwrap() as usize;
code.iter().fold(vec![vec![" ";x_max];y_max], |mut c, (x,y)| { c[*y as usize][*x as usize] = "█"; c })
};
println!("Ex2: The result is");
code.iter().for_each(|row| println!("{}", row.join("")));
}
fn fold(mut points: HashSet<(u32,u32)>, instruction: (bool,u32)) -> HashSet<(u32,u32)> {
let (x_axis, idx) = instruction;
if x_axis {
points.drain().map(|(x,y)| if x > idx { (2*idx - x, y) } else { (x,y) }).collect()
} else {
points.drain().map(|(x,y)| if y > idx { (x, 2*idx - y) } else { (x,y) }).collect()
}
}
|
