Rust

Pretty similar to the other rust answer. This definitely requires

of some form, but when done right, is very performant. 122ms for both.

#[cfg(test)]
mod tests {
    use std::collections::HashMap;

    fn count_solutions(
        design: &str,
        patterns: &[&str],
        seen_designs: &mut HashMap<String, i64>,
    ) -> i64 {
        if design.is_empty() {
            return 1;
        }
        if let Some(s) = seen_designs.get(design) {
            return *s;
        }
        let mut count = 0;
        for pattern in patterns {
            if design.starts_with(pattern) {
                count += count_solutions(&design[pattern.len()..], patterns, seen_designs);
            }
        }
        seen_designs.insert(design.to_string(), count);
        count
    }

    #[test]
    fn day19_both_test() {
        let input = std::fs::read_to_string("src/input/day_19.txt").unwrap();
        let parts = input.split_once("\n\n").unwrap();
        let patterns = parts.0.split(", ").collect::<Vec<&str>>();
        let designs = parts.1.split('\n').collect::<Vec<&str>>();

        let mut count = 0;
        let mut total = 0;
        let mut seen_designs = HashMap::new();
        for design in designs {
            let shortlist = patterns
                .iter()
                .filter_map(|p| {
                    if design.contains(p) {
                        return Some(*p);
                    }
                    None
                })
                .collect::<Vec<&str>>();
            let sol_count = count_solutions(design, &shortlist, &mut seen_designs);
            total += sol_count;
            count += (sol_count != 0) as usize;
        }
        println!("{}", count);
        println!("{}", total);
    }
}