Table of content

What is this
42nd Challenge
- Challenge
- Solution

What is this

The rules of the game are explained in my original post.

42nd Challenge

Challenge

Today I’m solving today’s AoC day 13 2021.

Solution

I have solved part1, part 2 will have to wait. I’m going to clean up all my solutions wants the calender is done. At the moment the goal is to stay at today’s challenge.

	use std::cmp::Ordering;

	fn main() {

	    let points:Vec<(u32,u32)> = DOTS.lines()
	        .map(|x|{
	            let k = x.split_once(',').unwrap();
	            (k.0.parse().unwrap(), k.1.parse().unwrap())
	        }).collect();

	    let n = points
	        .iter()
	        .fold(0,|max,inst| inst.0.max(max).max(inst.1))+1;

	    let folds:Vec<(Fold,u32)>= FOLDS.lines()
	        .map(|x|{
	            let k = x.split_once("=").unwrap();
	            match k.0 {
	                "fold along y" => (Fold::Up, k.1.parse::<u32>().unwrap()),
	                _ => (Fold::Left,k.1.parse().unwrap())
	            }
	        }).collect();

	    let mut i: Vec<u32> = points
	        .iter()
	        .map(|x| x.0 + (n) * x.1)
	        .collect();
	    i.sort();

	    i = match folds.get(0).unwrap() {
	        (Fold::Up, y) => {
	            points
	                .iter()
	                .map(|x| x.0 + (n) * x.1)
	                .map(|i| match i.cmp(&((n * n) / 2)) {
	                    Ordering::Greater => n * (n - (i - 1) / n) - (n - i % n),
	                    _ => i
	                }).collect()
	        },
	        (Fold::Left, x) => {
	            points.iter()
	                .filter(|i| i.0 != n/2)
	                .map(|i| i.0 + n*i.1)
	                .map(|i| match (i % n).cmp(&(n / 2)) {
	                    Ordering::Greater => (n-i%n-1) + (i / n) * n,
	                    _ => i
	                }).collect()
	        },
	        _ => vec![0]
	    };

	    i.sort();
	    i.dedup();

	    println!("{:?}",i.len());
	}

	#[derive(Debug)]
	enum Fold{
	    Up,
	    Left
	}


	const DOTS:&str = "0,0
	2,0
	3,0
	6,0
	9,0
	1,1
	4,1
	6,2
	10,2
	0,3
	4,3
	1,4
	3,4
	6,4
	8,4
	9,4
	10,4
	";

	const FOLDS:&str ="fold along x=5";

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