Insomniac code gorilla. I help maintain lemmy-ui and, to a lesser extent, Lemmy’s backend.

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  • 18 Comments
Joined 10 months ago
cake
Cake day: April 21st, 2024


  • Yeah, and many of those founders were rich businessmen who didn’t want to pay taxes to the king of England.

    They were pissy that the king made it illegal to expand westward and exterminate all of the indigenous people. They were all “no, actually, the British Empire isn’t evil enough. Let’s make an even bigger and eviller empire than the [at the time] most evil empire on Earth.”

    This is a human problem, not a national one.

    It is a national and class problem, not a human one. Human nature is a bs concept invented to sell the status quo.






  • Rust

    Kinda sorta got day 5 done on time.

    use std::cmp::Ordering;
    
    use crate::utils::{bytes_to_num, read_lines};
    
    pub fn solution1() {
        let mut lines = read_input();
        let rules = parse_rules(&mut lines);
    
        let middle_rules_sum = lines
            .filter_map(|line| {
                let line_nums = rule_line_to_list(&line);
                line_nums
                    .is_sorted_by(|&a, &b| is_sorted(&rules, (a, b)))
                    .then_some(line_nums[line_nums.len() / 2])
            })
            .sum::<usize>();
    
        println!("Sum of in-order middle rules = {middle_rules_sum}");
    }
    
    pub fn solution2() {
        let mut lines = read_input();
        let rules = parse_rules(&mut lines);
    
        let middle_rules_sum = lines
            .filter_map(|line| {
                let mut line_nums = rule_line_to_list(&line);
    
                (!line_nums.is_sorted_by(|&a, &b| is_sorted(&rules, (a, b)))).then(|| {
                    line_nums.sort_by(|&a, &b| {
                        is_sorted(&rules, (a, b))
                            .then_some(Ordering::Less)
                            .unwrap_or(Ordering::Greater)
                    });
    
                    line_nums[line_nums.len() / 2]
                })
            })
            .sum::<usize>();
    
        println!("Sum of middle rules = {middle_rules_sum}");
    }
    
    fn read_input() -> impl Iterator<Item = String> {
        read_lines("src/day5/input.txt")
    }
    
    fn parse_rules(lines: &mut impl Iterator<Item = String>) -> Vec<(usize, usize)> {
        lines
            .take_while(|line| !line.is_empty())
            .fold(Vec::new(), |mut rules, line| {
                let (a, b) = line.as_bytes().split_at(2);
                let a = bytes_to_num(a);
                let b = bytes_to_num(&b[1..]);
    
                rules.push((a, b));
    
                rules
            })
    }
    
    fn rule_line_to_list(line: &str) -> Vec<usize> {
        line.split(',')
            .map(|s| bytes_to_num(s.as_bytes()))
            .collect::<Vec<_>>()
    }
    
    fn is_sorted(rules: &[(usize, usize)], tuple: (usize, usize)) -> bool {
        rules.iter().any(|&r| r == tuple)
    }
    

    Reusing my bytes_to_num function from day 3 feels nice. Pretty fun challenge.


  • Rust

    I’m a day behind on this one due to a lot of work with my job and school.

    use std::iter::zip;
    
    use crate::utils::read_lines;
    
    pub fn solution1() {
        let puzzle = read_puzzle();
    
        let horizontal_sum = puzzle
            .iter()
            .map(|line| {
                line.windows(4)
                    .filter(|window| {
                        matches!(window, [b'X', b'M', b'A', b'S'] | [b'S', b'A', b'M', b'X'])
                    })
                    .count() as u32
            })
            .sum::<u32>();
        let vertical_and_diagonal_sum = puzzle
            .windows(4)
            .map(|window| {
                count_xmas(window, (0, 0, 0, 0))
                    + count_xmas(window, (0, 1, 2, 3))
                    + count_xmas(window, (3, 2, 1, 0))
            })
            .sum::<u32>();
    
        println!(
            "XMAS count = {}",
            horizontal_sum + vertical_and_diagonal_sum
        );
    }
    
    pub fn solution2() {
        let puzzle = read_puzzle();
    
        let sum = puzzle
            .windows(3)
            .map(|window| {
                zip(
                    window[0].windows(3),
                    zip(window[1].windows(3), window[2].windows(3)),
                )
                .map(|(a, (b, c))| (a, b, c))
                .filter(|tuple| {
                    matches!(
                        tuple,
                        ([b'M', _, b'M'], [_, b'A', _], [b'S', _, b'S'])
                            | ([b'S', _, b'M'], [_, b'A', _], [b'S', _, b'M'])
                            | ([b'M', _, b'S'], [_, b'A', _], [b'M', _, b'S'])
                            | ([b'S', _, b'S'], [_, b'A', _], [b'M', _, b'M'])
                    )
                })
                .count() as u32
            })
            .sum::<u32>();
    
        println!("X-MAS count = {sum}");
    }
    
    fn count_xmas(
        window: &[Vec<u8>],
        (skip0, skip1, skip2, skip3): (usize, usize, usize, usize),
    ) -> u32 {
        zip(
            window[0].iter().skip(skip0),
            zip(
                window[1].iter().skip(skip1),
                zip(window[2].iter().skip(skip2), window[3].iter().skip(skip3)),
            ),
        )
        .map(|(a, (b, (c, d)))| (a, b, c, d))
        .filter(|tup| matches!(tup, (b'X', b'M', b'A', b'S') | (b'S', b'A', b'M', b'X')))
        .count() as u32
    }
    
    fn read_puzzle() -> Vec<Vec<u8>> {
        read_lines("src/day4/input.txt")
            .map(|line| line.into_bytes())
            .collect()
    }
    

    The standard library windows method and pattern matching have been carrying me this year so far.


  • Rust

    use crate::utils::read_lines;
    
    pub fn solution1() {
        let lines = read_lines("src/day3/input.txt");
        let sum = lines
            .map(|line| {
                let mut sum = 0;
                let mut command_bytes = Vec::new();
                for byte in line.bytes() {
                    match (byte, command_bytes.as_slice()) {
                        (b')', [.., b'0'..=b'9']) => {
                            handle_mul(&mut command_bytes, &mut sum);
                        }
                        _ if matches_mul(byte, &command_bytes) => {
                            command_bytes.push(byte);
                        }
                        _ => {
                            command_bytes.clear();
                        }
                    }
                }
    
                sum
            })
            .sum::<usize>();
    
        println!("Sum of multiplication results = {sum}");
    }
    
    pub fn solution2() {
        let lines = read_lines("src/day3/input.txt");
    
        let mut can_mul = true;
        let sum = lines
            .map(|line| {
                let mut sum = 0;
                let mut command_bytes = Vec::new();
                for byte in line.bytes() {
                    match (byte, command_bytes.as_slice()) {
                        (b')', [.., b'0'..=b'9']) if can_mul => {
                            handle_mul(&mut command_bytes, &mut sum);
                        }
                        (b')', [b'd', b'o', b'(']) => {
                            can_mul = true;
                            command_bytes.clear();
                        }
                        (b')', [.., b't', b'(']) => {
                            can_mul = false;
                            command_bytes.clear();
                        }
                        _ if matches_do_or_dont(byte, &command_bytes)
                            || matches_mul(byte, &command_bytes) =>
                        {
                            command_bytes.push(byte);
                        }
                        _ => {
                            command_bytes.clear();
                        }
                    }
                }
    
                sum
            })
            .sum::<usize>();
    
        println!("Sum of enabled multiplication results = {sum}");
    }
    
    fn matches_mul(byte: u8, command_bytes: &[u8]) -> bool {
        matches!(
            (byte, command_bytes),
            (b'm', [])
                | (b'u', [.., b'm'])
                | (b'l', [.., b'u'])
                | (b'(', [.., b'l'])
                | (b'0'..=b'9', [.., b'(' | b'0'..=b'9' | b','])
                | (b',', [.., b'0'..=b'9'])
        )
    }
    
    fn matches_do_or_dont(byte: u8, command_bytes: &[u8]) -> bool {
        matches!(
            (byte, command_bytes),
            (b'd', [])
                | (b'o', [.., b'd'])
                | (b'n', [.., b'o'])
                | (b'\'', [.., b'n'])
                | (b'(', [.., b'o' | b't'])
                | (b't', [.., b'\''])
        )
    }
    
    fn handle_mul(command_bytes: &mut Vec<u8>, sum: &mut usize) {
        let first_num_index = command_bytes
            .iter()
            .position(u8::is_ascii_digit)
            .expect("Guarunteed to be there");
        let comma_index = command_bytes
            .iter()
            .position(|&c| c == b',')
            .expect("Guarunteed to be there.");
    
        let num1 = bytes_to_num(&command_bytes[first_num_index..comma_index]);
        let num2 = bytes_to_num(&command_bytes[comma_index + 1..]);
    
        *sum += num1 * num2;
        command_bytes.clear();
    }
    
    fn bytes_to_num(bytes: &[u8]) -> usize {
        bytes
            .iter()
            .rev()
            .enumerate()
            .map(|(i, digit)| (*digit - b'0') as usize * 10usize.pow(i as u32))
            .sum::<usize>()
    }
    

    Definitely not my prettiest code ever. It would probably look nicer if I used regex or some parsing library, but I took on the self-imposed challenge of not using third party libraries. Also, this is already further than I made it last year!





  • Rust

    use crate::utils::read_lines;
    
    pub fn solution1() {
        let reports = get_reports();
        let safe_reports = reports
            .filter(|report| report.windows(3).all(window_is_valid))
            .count();
    
        println!("Number of safe reports = {safe_reports}");
    }
    
    pub fn solution2() {
        let reports = get_reports();
        let safe_reports = reports
            .filter(|report| {
                (0..report.len()).any(|i| {
                    [&report[0..i], &report[i + 1..]]
                        .concat()
                        .windows(3)
                        .all(window_is_valid)
                })
            })
            .count();
    
        println!("Number of safe reports = {safe_reports}");
    }
    
    fn window_is_valid(window: &[usize]) -> bool {
        matches!(window[0].abs_diff(window[1]), 1..=3)
            && matches!(window[1].abs_diff(window[2]), 1..=3)
            && ((window[0] > window[1] && window[1] > window[2])
                || (window[0] < window[1] && window[1] < window[2]))
    }
    
    fn get_reports() -> impl Iterator<Item = Vec<usize>> {
        read_lines("src/day2/input.txt").map(|line| {
            line.split_ascii_whitespace()
                .map(|level| {
                    level
                        .parse()
                        .expect("Reactor level is always valid integer")
                })
                .collect()
        })
    }
    

    Definitely trickier than yesterday’s. I feel like the windows solution isn’t the best, but it was what came to mind and ended up working for me.


  • Rust

    I’m doing it in Rust again this year. I stopped keeping up with it after day 3 last year, so let’s hope I last longer this time around.

    Solution Spoiler Alert
    use std::collections::HashMap;
    
    use crate::utils::read_lines;
    
    pub fn solution1() {
        let (mut id_list1, mut id_list2) = get_id_lists();
    
        id_list1.sort();
        id_list2.sort();
    
        let total_distance = id_list1
            .into_iter()
            .zip(id_list2)
            .map(|(left, right)| (left - right).abs())
            .sum::<i32>();
    
        println!("Total distance = {total_distance}");
    }
    
    pub fn solution2() {
        let (id_list1, id_list2) = get_id_lists();
    
        let id_count_map = id_list2
            .into_iter()
            .fold(HashMap::<_, i32>::new(), |mut map, id| {
                *map.entry(id).or_default() += 1i32;
    
                map
            });
    
        let similarity_score = id_list1
            .into_iter()
            .map(|id| id * id_count_map.get(&id).copied().unwrap_or_default())
            .sum::<i32>();
    
        println!("Similarity score = {similarity_score}");
    }
    
    fn get_id_lists() -> (Vec<i32>, Vec<i32>) {
        read_lines("src/day1/input.txt")
            .map(|line| {
                let mut ids = line.split_whitespace().map(|id| {
                    id.parse::<i32>()
                        .expect("Ids from input must be valid integers")
                });
    
                (
                    ids.next().expect("First Id on line must be present"),
                    ids.next().expect("Second Id on line must be present"),
                )
            })
            .unzip()
    }
    

    I’m keeping my solutions up on GitHub.


  • Yeesh, I thought you were being hyperbolic, but it really is that bad! He even has this massive self report towards the end:

    And how do you avoid being punished? There are two ways. One that works; and one that doesn’t. The one that doesn’t work is to design everything up front before coding. The one that does avoid the punishment is to override all the safeties.

    And so you will declare all your classes and all your functions open. You will never use exceptions. And you will get used to using lots and lots of ! characters to override the null checks and allow NPEs to rampage through your systems.

    Uncle Bob must be the kind of guy who makes all of his types any when writing Typescript.



  • Sleepless One@lemmy.mltoAsklemmy@lemmy.mlAre you a 'tankie'
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    9 months ago

    Yes.

    The last time I smiled was on August 19th, 1991. I wear a dirty ushanka at all times, do not shave, and only take cold sponge baths because hot running water is bourgeoisie decadence. Every day at exactly noon I have the same meal of an expired Maoist MRE I store in a pit covered in old issues of a revolutionary newspaper. I sleep in a bed made of flags from every failed revolution so that they are never forgotten. In the evenings I stare at a picture of vodka by candlelight, but I do not allow myself to drink because there is nothing to celebrate. Every local org has banned me after I attempted to split it by assassinating the leadership. There is no plumbing in my house I shit in a brass bucket with a picture of Gonzalo and Deng french kissing in the bottom of it. My house is actually an overturned T34 in an abandoned junkyard in Wisconsin. I have a single friend in this world and it is a tapeworm named Bordiga that I met after ingesting spoiled borscht on 9/11 in the ruins of building 7 (I blew it up after finding that a nominally leftist NGO inside of it wasn’t sufficiently anti-imperialist, the attacks on the world trade center were a perfect revolutionary moment for me to enact direct praxis against liberalism). My source of income is various MLM schemes in the former soviet bloc that have been running for so long no one remembers who I am, they just keep sending money. I have not paid taxes since McGovern lost the Democratic nomination for president and my faith in electoralism died more brutally than my childhood dog after it got into an entire jar of tylenol. I own 29 fully automatic rusted kalashnikovs and three crates of ammunition entirely incompatible with them or any other firearms I own. My double PHD in marxist economics and 18th century Swiss philosophy (required to understand Engels) sits over the fireplace of my home, my fireplace is a salvaged drum from a 1950s washing machine that was recalled for locking children inside of it. I chose that washing machine model on purpose because I am anti-natalist. During the latest BLM protests I firebombed a Nikes outlet in the middle of a peaceful candlelit vigil. William F Buckley and I wrote hatemail to one another for 47 years until my final letter gave him an aneurysm. The only water I drink is from puddles. George Lucas and I dropped acid together during an MKULTRA southern baptist summer camp and he went on to write the movie Willow about our time together. The best way to test whether an electrical wire is live is to drool on it and shrimp salad is racist. You can make an IED out of potassium and the instructions are online thanks to Timothy McVey, who was actually a committed antifascist communist slandered by the deep state as part of operation condor. Every time a liberal files a restraining order against me, I carve a mark into the wall. I am running out of walls. When Amerika finally collapses I will be ready to lead the revolution. I am very smart and people like being around me.