Advent of Code 2023 Day 6 Optimizations

fastest_day6_part2.rs

// time:   [1.8843 µs 1.8897 µs 1.8955 µs]
pub fn original(input: &[u8]) -> Option<usize> {
    let mut idx = 0;
    'outer: while idx + 13 < input.len() {
        let mut state = 0;
        for (next_idx, byte) in input[idx..idx + 14].iter().enumerate().rev() {
            let bit_idx = byte % 32;
            if state & (1 << bit_idx) != 0 {
                idx += next_idx + 1;
                continue 'outer;
            }
            state |= 1 << bit_idx;
        }
        return Some(idx);
    }
    return None;
}

// time:   [972.80 ns 980.40 ns 987.77 ns]
pub fn my_fastest(input: &[u8]) -> Option<usize> {
    let mut idx = 0;
    while let Some(slice) = input.get(idx..idx + 14) {
        let mut state = 0u32;

        if let Some(pos) = slice.iter().rposition(|byte| {
            let bit_idx = byte % 32;
            let ret = state & (1 << bit_idx) != 0;
            state |= 1 << bit_idx;
            ret
        }) {
            idx += pos + 1;
        } else {
            return Some(idx);
        }
    }
    return None;
}

// time:   [6.6444 µs 6.6834 µs 6.7255 µs]
pub fn benny(input: &[u8]) -> Option<usize> {
    let mut filter = 0u32;
    input
        .iter()
        .take(14 - 1)
        .for_each(|c| filter ^= 1 << (c % 32));
    input.windows(14).position(|w| {
        let first = w[0];
        let last = w[w.len() - 1];
        filter ^= 1 << (last % 32);
        let res = filter.count_ones() == 14 as _;
        filter ^= 1 << (first % 32);
        res
    })
}

//  time:   [2.7528 µs 2.7618 µs 2.7721 µs]
#[cfg_attr(target_arch = "x86_64", target_feature(enable = "popcnt"))]
pub unsafe fn benny_popcnt(input: &[u8]) -> Option<usize> {
    let mut filter = 0u32;
    input
        .iter()
        .take(14 - 1)
        .for_each(|c| filter ^= 1 << (c % 32));
    input.windows(14).position(|w| {
        let first = w[0];
        let last = w[w.len() - 1];
        filter ^= 1 << (last % 32);
        let res = filter.count_ones() == 14 as _;
        filter ^= 1 << (first % 32);
        res
    })
}

my_benchmark.rs

use std::time::Duration;

use aoc_2022::*;
use criterion::{criterion_group, criterion_main, Criterion};

pub fn criterion_benchmark(c: &mut Criterion) {
    let input = "rnttlvtttmnmpmhpmmzvmmhpmmnrntnnsnrnndvnddmbbtptssjcczmmbwmbmwwmmflfggwzzhjjgppwrwdwqwbbbmwbwgggqccmlmdmgdgqgpqgpgzzndddgdbbsvvfsfppwjwzjjcnjccwrwrprgppbpddnccjggfrggqngqgdqgddvsshqhmqqfvqvlvwvnwwmccrpcczvcczzgsgwwlggqsggmdgglblpblltbbzrbzzcscgccwssbddsmddzzvvhjjwjwrjwrwfftmttplldnllqttdhddmvdmmhsmsmqsqwqpqbpqppqdppbnpnhhppjbbrzrbrggdbddnrdrzrdrpdppzzfzrzgzllwlwzlllwtltslttlmtmqqbbzmzhmmjjwrjrrnzrzhzmmtbbrppmmfddjhdjdsdllrbbpfphpzpwwjvwwdpwpzwwzrrfnfwwfbbpttzjtjptpvvsfvvljjrzzmdmsddpvpgvvdcdwcwhwghwggrjjhdjhddzhhwbhwbwwbrwwrfrmfrfvrfftzzqrzqrqtrqtrqtrqttgctclcwlwwvqqnlnqlnnndmnmggznzhzqzggzrzbbrwbrwrvvscvvmvhmvvbsbjsjfjpfpqpbbbbjtjptpprnndpnnrsswffmnnjhhpqhqwhhbwhbhgbbfrbrjjpmjmzzdzjdjffcvvtwttrrcscvcncqcfcwwpgpfptpcpspllcfcssgbglgdllcdcmcpcqclctcvtvvbhbbdhhczhzshzhbhchzchchlcllwswqqmpmbbqwwzgzhggczgzffsgggjjlcjjpnjjfqjfjvfvrfrlrvvpfpcfcbffnmfmbmbgggplldblddvcvjcvvmbmmmrvrvvnhhqttgdgvdgdqgddcsclljplpbbsvbsbfsffshsgslsllzztggttfccctwtswwrvwvnnfbnnvjnvvlgvvfppmvpmmvpmmcttjffgsffcllncntcncfclcgcppvdvpvrvbrrnnvrvhrvrzvrvnrvrdrnrqrnngsshqhcqqbfqqzmmmzjzqztznttjffqzfqfbqqsggclgclcddtqqdppbjppqvpqvvmqmqnqcnqcqcqvqjqzqbzzbrrgfgddgtgnnpjjbzjjbbtstzszwswggfffmnnpllfvvnwnpwpqwqwlllqlmmzcmcrcmrcmrcrffnrnssjjrdjjwwqgwqgqdggwzwjzzbfbpptctchthbbbqsqggrllldwdffvwwlrwwljwjnncmmjmvjmmqnnmrrgjgvvpqqbppqlpqllqnqdndwwlppcjcdjjcnnmddffgjjrwjrwjjhvhqvhhfssrtsrsgrrwjwhhbqqpzzrdrhrqhrqrprqqmllsszhzllcdllpmpbbmsmjjmwmssvlslwwmtwmmgvgcvggzcgzgddsjsjfsssftfcchhfmfcmcpcpvcppqggjddljjbttwrrhghqggpghgngzngznnzqnnssqlqmqbmmmqdqqhttnqqjhhphrhccbggmjjpwpbwpprdrvvjzvvtctzzmpphwpwdpdvvhbvvdvsdsjdjbdjdljjstswttnhhbfffmnngddlglqggvzvlzvzqqvbqbvbjbnjjsvjjwpjjzshrdtrjttvqnbltrfpvnztrwzrtgjpzgqdjfglqgjrgdzbhqpghdbfhlfjhbfjfjppfgljmgwljlsbmltgztthnzvdrgqlgddvqhzctdgcphfqvnpjjgzwqfvnhvzdrwtpgfdjpqnfshslqmplcprdntnhqqbqptwzvdddhcjcqrfhjqnjvpnhttblwgjwlfwntdchgfjmdbgtqtdgnzbqwzzcltwtmtqtdbvjtfvlzpcvgmrfqwfhwqmhvwhftzgmhshffnjwqbvztszsrrglqvhfpqmbnqjsfnwdwgdtmztbvqrmztfctmvptbwnfzfgdztjgnqsrsqqqnrpgzsqszzwwwgqnnnrdzhzdbqjgbvncprzcjqchzfgnclbrmphbsdwwpvwjwlbshhgjfbhjjtdqrmrcjfnrrhqrpsbglthzpvfglqspttdpwlljhnlrjpzchbrqcgtmcscjnwvpztfjdcwbnbgmbpgdthgnhbrtwftnscbsrndghbslflpcpjwbcjnhzcwdcslmzqbtrlnzmntlpjcsctnsqwtbffqlhfgcsflvfwnmczvsbflnnnzpfjfrcwhhcbtbjcbghtcwcgdbrwrgfgvpwtcwlwcmnmrtcrjbwtwlrfstztsghfvrfjzzpswpqfqpvqstvbhqfjlgmtdlhqrhwzqpnqpllnlgzwptbgftmblqcwfcllbwfzdhrndfrvdvwzqvhnghlzvhldnnvrgqvlpfdnpmcgddjmstzsqfvzwftflrwtzqwjbbqhjpfbdztdfsgsztvvrvslgspgpdcmwszdfsddqhpzpsjgqmgzqvhchlgrmcmzwzbtwfphvgcdmhfdczhffgmqpncdjszzgwfvwsqddvbcgngbjwhmphjsmjthvbthhfwdtqmjctcmdpqpsdrnrzdgzgzctbhwsgvtjgwjbsnnjmpmqgwrnqfqbpnrpddjsrsvmcshhthwfrwmqsrjhlsrgfzvwmdzhwrvchppqldghgzflrnwqnvntmtdwmrpgbdbzvcmnqstzntvllcgzsnvrhqzsfncznhgrggmvrmgsqmhbdsjbsqqhzppfcwdrgdvfjdscrvpwtsdmcnczwbbjhvddprwtzfwslcfdcrqfszcgmhtdfvlqzqtvwngzvmmqcrqpzwzhggjnphsrmnctnfhtppglspnvzrsqfgzdfrrwbzbqwvbvbnzgmdrqrnsvdpvlgcmnggsbmbtfwrvdjrtgtgcqscnfpgswgsngdqnnscffdcnlrcpdpcbpzvqcrtjhlwvgnfhhqmprthrtcvcjjwgprqqdwfbgmzlwttjpvcjzfwbdhvngsjpgtqsvbldbcvhjhzbjzblqtqhlnbzzqfcpnzdhbplztcgvzhbgshqbccgwzhftqvtwzbwmnfrsgphhhgtsmwlqhlcchtbtggqwmbdthhmqqjtfdvfpddfdrtfjbpmwtcbfnrhwcnpdqrdtsfdmjfzdwwgnftnwpssgqtlpdbwhnzcnfmppclsswbhcdghpnslwjznqszgdtrnpncsqsnbrplrfwpbnfnvttlzcjtvhzcpzmhfsfzfjlzqqnprpdvwbfthmrswqrcqqwrnwzmgjqqsnqdblssmhngjjvprmqbswtgzzvprwhrgjqshvmwzgrgfmzlgrtzbmdlzncwqdftfsndvdfmmplswdbjtbcbvcvtpjvrqpghczpqvvpqwfbfhllbpvrrfsmsjhqbldcrwvzvcvzfffqvplbfbdbwctbjsljlfwtbcnpsbtpmcqgdvltmztvrcfsprbnvwplwhncgsdnrdmqnmcvpvvrlmlwtgvrnwvzsfctdlcfvtgqmpnbwcbwvfpmqnbjvwffpjtvvgflhrnlngrzhhttdtdbvscftsqtvbrgzfgsjvwhzjcbsqcttlgwmhhvjhwhgmmdtflfdbvnhgcblqmwjfsqnngjqfbvdnsfbgwjfhpgdgvhpbvlrtpcpvhrbtqpbffzcqrvbqwvqmmrcwtnvcgwvsqzvrwdbcnjshbnbftmmvrmjvgfdwbsjvqfdwnnvqqhbmshcrclrwhfhbtnwqvmrrvdwgcwcsrhdbqndsthmrmbjhttjtzmlflbrmhlcgsbdjcjcvwcjffnqrntpflrgfcngpchtrzpnflwjvcgbwtsnjfqsggwmwhdvbzdpjmtwlmrslnjsndjtgjmmwmdgtnfrztppzqvqhbfzqpsdhvsshddlzwcmsndrpqhndsrjnngnmgmzrvchwlqgdnbssbhpbpgwpsrcnbphpslvqplhpgdhmrnwwjmhvnsfjmrfwtvjjrmgptvjffhbgpmfgmgrcjrwqhccssrqjpljbpwcvsfdtmbhzsmsjsgblgpcqszsttfclrjcnsslmngmbmwqfhddbvmbvwmrmvglsl".as_bytes();

    let mut group = c.benchmark_group("day6_part2");

    group.measurement_time(Duration::from_secs(10));

    group.bench_with_input("original", input, |b, s| b.iter(|| original(s)));

    group.bench_with_input("my_fastest", input, |b, s| b.iter(|| my_fastest(s)));
    
    group.bench_with_input("benny", input, |b, s| b.iter(|| benny(s)));

    group.bench_with_input("benny_popcnt", input, |b, s| b.iter(|| unsafe { benny_popcnt(s) }));

    group.finish();
}

criterion_group!(benches, criterion_benchmark);
criterion_main!(benches);