Table of content

What is this :grey_question:

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

36th Challenge

Challenge

Today I’m solving today’s AoC day 6 2021.

Solution :white_check_mark:

Ok, maybe slightly different approach of learning today. I’m going to look at the functions used by other rust solutions before starting. If I don’t know them I will learn their meaning before I start. Lets take a look at the Reddit Mega Thread for Day 6.

Skimming through the thread I found the following functional calls, seems nothing too special going on today. Maybe I need to add the whole scope into my search.

rotate_left(..)

	fn main() {

	    let mut n = 0x12345678u32;
	    
	    for _ in 0..9 {

	        println!("{:#x}",n);
	        n=n.rotate_left(4);
	    }
	}

	/* outputs :
	0x12345678
	0x23456781
	0x34567812
	0x45678123
	0x56781234
	0x67812345
	0x78123456
	0x81234567
	0x12345678 */

include_str!(“”)

This adds a string literal into the code source. I prefer to just create one in my code with const INPUT:&str..

bench()

Used to benchmark a method, if you’re interested in the speed of your code which I’m currently not.

let mut state = [0u64; 9];

Initalizing an array with u64int length 9.

x.or_insert(0)

See the rust doc.

	use std::collections::HashMap;

	let mut map: HashMap<&str, u32> = HashMap::new();

	map.entry("poneyland").or_insert(3);
	assert_eq!(map["poneyland"], 3);

	*map.entry("poneyland").or_insert(10) *= 2;
	assert_eq!(map["poneyland"], 6);

x.for_each()

Like most languages, rust has a for_each iteration method. See Stackoverflow thread on when to use for_each.

use itertools::{iterate, Itertools};

This is a handy dandy toolbox for powerful iterator operations. I defentely want to invest some time to get to know the scope of the lib.

Ok that didn’t help much. The first part was easy but I implemented it badly keeping track of every fishes individual clock rather than the number of fishes with a given clock. I ended up cheating off of the answer of Github User yorhodes after trying recursive approach, filter approach and what not but always trying to keep track of every fish … oh well better luck next time.

Oh well better luck next time.