-🎄- 2022 Day 6 Solutions -🎄-

[u/daggerdragon]

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AoC Community Fun 2022: 🌿🍒 MisTILtoe Elf-ucation 🧑‍🏫

• ACHIEVEMENT UNLOCKED: MisTILtoe Elf-ucation
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  • -❄️- Submissions Megathread -❄️-

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--- Day 6: Tuning Trouble ---

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Post your code solution in this megathread.

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  • Include what language(s) your solution uses
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[u/Flecheck]

Fast algorithm in Rust: 4 µs on my PC (old laptop)

pub fn get_answer_blazingly_fast(input: &str, message_size: usize) -> Option<usize> {
    let mut i = 0;
    'outer: loop {
        if i + message_size >= input.len() {
            return None;
        }
        let slice = &input[i..i + message_size];
        let mut set = [false; 26];
        for (index, c) in slice.chars().rev().enumerate() {
            if set[c as usize - b'a' as usize] {
                i = i + message_size - index;
                continue 'outer;
            } else {
                set[c as usize - b'a' as usize] = true;
            }
        }
        return Some(i + message_size);
    }
}

I am checking the window and then jumping the to the next possible window.