day 20 part 1 done

2023/day-20/Cargo.toml

@@ -0,0 +1,15 @@
+[package]
+name = "day-20"
+version.workspace = true
+edition.workspace = true
+authors.workspace = true
+repository.workspace = true
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]
+nom = { workspace = true }
+itertools = {workspace = true }
+
+[dev-dependencies]
+rstest.workspace = true

2023/day-20/src/lib.rs

@@ -0,0 +1,4 @@
+pub mod part1;
+pub use crate::part1::*;
+pub mod part2;
+pub use crate::part2::*;

2023/day-20/src/main.rs

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+#![warn(clippy::all, clippy::pedantic)]
+
+use day_20::part1;
+use day_20::part2;
+
+fn main() {
+    let input = include_str!("./input.txt");
+    let part1_result = part1(input);
+    println!("part 1: {part1_result}");
+    let part2_result = part2(input);
+    println!("part 2: {part2_result}");
+}

2023/day-20/src/part1.rs

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+#![warn(clippy::all, clippy::pedantic)]
+
+use std::collections::{BTreeMap, HashMap, VecDeque};
+
+use nom::{
+    branch::alt,
+    bytes::complete::tag,
+    character::complete,
+    combinator::opt,
+    multi::separated_list1,
+    sequence::{separated_pair, tuple},
+    IResult,
+};
+
+#[derive(Debug, Clone, PartialEq, Eq, PartialOrd, Ord, Hash)]
+enum ModuleType<'a> {
+    Broadcast,
+    FlipFlop(bool),
+    Conjunction(BTreeMap<&'a str, bool>),
+}
+
+#[derive(Debug, Clone, PartialEq, Eq, PartialOrd, Ord, Hash)]
+struct Module<'a> {
+    pub mod_type: ModuleType<'a>,
+    pub connections: Vec<&'a str>,
+}
+
+impl<'a> Module<'a> {
+    fn handle_pulse(&self, from: &'a str, is_high_pulse: bool) -> (Self, Option<bool>) {
+        let mut m = self.clone();
+        match (&m.mod_type, is_high_pulse) {
+            (ModuleType::Broadcast, _) => (m, Some(is_high_pulse)),
+            (ModuleType::FlipFlop(_), true) => (m, None),
+            (ModuleType::FlipFlop(is_on), false) => {
+                let was_on = *is_on;
+                m.mod_type = ModuleType::FlipFlop(!is_on);
+                (m, Some(!was_on))
+            }
+            (ModuleType::Conjunction(map), is_high_pulse) => {
+                let mut map = map.clone();
+                map.insert(from, is_high_pulse);
+                m.mod_type = ModuleType::Conjunction(map.clone());
+                (m, Some(!map.values().all(|x| *x)))
+            }
+        }
+    }
+}
+
+fn push_button<'a>(
+    mut setup: BTreeMap<&'a str, Module<'a>>,
+) -> (BTreeMap<&'a str, Module<'a>>, (usize, usize)) {
+    let mut queue = VecDeque::from(vec![("broadcaster", None, false)]);
+    let mut low_signals = 1;
+    let mut high_signals = 0;
+    //println!("push the button");
+    loop {
+        //println!("{queue:?}");
+        if queue.is_empty() {
+            break;
+        }
+        let (current_label, from, signal) = queue.pop_front().unwrap();
+        let Some(current) = setup.get(current_label) else {
+            // if not found then in a sink
+            continue;
+        };
+
+        let (new_current, signal_to_send) = current.handle_pulse(from.unwrap_or("button"), signal);
+        if let Some(signal_to_send) = signal_to_send {
+            new_current
+                .connections
+                .iter()
+                .map(|x| (*x, Some(current_label), signal_to_send))
+                /*.inspect(|(x, _, is_high_signal)| {
+                    println!(
+                        "{current_label} -{}-> {x}",
+                        if *is_high_signal { "high" } else { "low" }
+                    )
+                })*/
+                .for_each(|x| {
+                    queue.push_back(x);
+                    low_signals += usize::from(!signal_to_send);
+                    high_signals += usize::from(signal_to_send);
+                });
+        }
+        setup.insert(current_label, new_current);
+    }
+    (setup, (low_signals, high_signals))
+}
+
+fn setup_to_key(setup: &BTreeMap<&str, Module>) -> String {
+    setup
+        .iter()
+        .map(|(label, module)| match &module.mod_type {
+            ModuleType::Broadcast => (*label).to_string(),
+            ModuleType::FlipFlop(is_on) => {
+                if *is_on {
+                    label.to_uppercase()
+                } else {
+                    label.to_lowercase()
+                }
+            }
+            ModuleType::Conjunction(map) => {
+                "%".to_string()
+                    + *label
+                    + &map
+                        .iter()
+                        .map(|(key, value)| {
+                            if *value {
+                                key.to_uppercase()
+                            } else {
+                                key.to_lowercase()
+                            }
+                        })
+                        .collect::<String>()
+                    + "%"
+            }
+        })
+        .collect::<String>()
+}
+
+/// day 20 part 1 of aoc 2023
+///
+/// # Arguments
+/// - input the input for today's puzzle
+///
+/// # Panics
+/// panics whne it cannot parse the input OR when ever the number of game numbers is greater than
+#[must_use]
+pub fn part1(input: &str) -> String {
+    let (_, mut setup) = parse_input(input).expect("aoc input always valid");
+    let mut cache = HashMap::new();
+    let mut high;
+    let mut low;
+    let mut high_count = 0;
+    let mut low_count = 0;
+    let mut key = setup_to_key(&setup);
+    let mut next_key;
+    let mut iteration = 0;
+    let cycle_start = loop {
+        if iteration >= 1000 {
+            break iteration;
+        }
+        (setup, (low, high)) = push_button(setup);
+        next_key = setup_to_key(&setup);
+        if let Some(x) = cache.insert(key, (high, low, next_key.clone(), iteration)) {
+            break x.3;
+        }
+        high_count += high;
+        low_count += low;
+        key = next_key;
+        iteration += 1;
+    };
+    if cycle_start < 1000 {
+        let cycle_len = iteration - cycle_start;
+        let nnn = 1000 - iteration;
+        let number_of_cycles = nnn / cycle_len;
+        let left_over_pushes = nnn % cycle_len;
+        let (cycle_high, cycle_low) = cache
+            .iter()
+            .filter_map(|(_, (high, low, _, iter))| {
+                (*iter >= cycle_start && *iter <= iteration).then_some((high, low))
+            })
+            .fold((0, 0), |(high_total, low_total), (high, low)| {
+                (high_total + high, low_total + low)
+            });
+        high_count += number_of_cycles * cycle_high;
+        low_count += number_of_cycles * cycle_low;
+        let (left_high, left_low) = cache
+            .iter()
+            .filter_map(|(_, (high, low, _, iter))| {
+                (*iter >= cycle_start && *iter <= iteration).then_some((high, low))
+            })
+            .take(left_over_pushes)
+            .fold((0, 0), |(high_total, low_total), (high, low)| {
+                (high_total + high, low_total + low)
+            });
+        high_count += left_high;
+        low_count += left_low;
+    }
+
+    (high_count * low_count).to_string()
+}
+
+fn parse_line(input: &str) -> IResult<&str, (&str, Module)> {
+    let (input, mod_type) = opt(alt((tag("%"), tag("&"))))(input)?;
+    let (input, (label, connections)) = separated_pair(
+        complete::alpha1,
+        tuple((complete::space0, tag("->"), complete::space0)),
+        separated_list1(tuple((tag(","), complete::space0)), complete::alpha1),
+    )(input)?;
+    let mod_type = match mod_type {
+        Some("%") => ModuleType::FlipFlop(false),
+        Some("&") => ModuleType::Conjunction(BTreeMap::new()),
+        None => ModuleType::Broadcast,
+        Some(x) => unimplemented!("No module type {x}"),
+    };
+    Ok((
+        input,
+        (
+            label,
+            Module {
+                mod_type,
+                connections,
+            },
+        ),
+    ))
+}
+
+fn parse_input(input: &str) -> IResult<&str, BTreeMap<&str, Module>> {
+    let (input, mut lines) = separated_list1(complete::line_ending, parse_line)(input)
+        .map(|(input, v)| (input, v.into_iter().collect::<BTreeMap<_, _>>()))?;
+    let conjunctions = lines
+        .iter()
+        .filter_map(|(key, module)| {
+            if let ModuleType::Conjunction(_) = module.mod_type {
+                Some(*key)
+            } else {
+                None
+            }
+        })
+        .map(|conjunction| {
+            (
+                conjunction,
+                lines
+                    .iter()
+                    .filter_map(|(key, module)| {
+                        module.connections.contains(&conjunction).then_some(*key)
+                    })
+                    .collect::<Vec<_>>(),
+            )
+        })
+        .collect::<BTreeMap<_, _>>();
+    lines
+        .iter_mut()
+        .filter(|(key, _)| conjunctions.contains_key(*key))
+        .for_each(|(key, module)| {
+            conjunctions.get(key).unwrap().iter().for_each(|to_key| {
+                if let ModuleType::Conjunction(tos) = &mut module.mod_type {
+                    tos.insert(to_key, false);
+                }
+            });
+        });
+    Ok((input, lines))
+}
+
+#[cfg(test)]
+mod test {
+    use rstest::rstest;
+
+    use super::*;
+
+    #[rstest]
+    #[case(
+        "broadcaster -> a, b, c
+%a -> b
+%b -> c
+%c -> inv
+&inv -> a",
+        "32000000"
+    )]
+    #[case(
+        "broadcaster -> a
+%a -> inv, con
+&inv -> b
+%b -> con
+&con -> output",
+        "11687500"
+    )]
+    fn part1_works(#[case] input: &str, #[case] expected: &str) {
+        let result = part1(input);
+        assert_eq!(result, expected);
+    }
+}

2023/day-20/src/part2.rs

@@ -0,0 +1,19 @@
+#![warn(clippy::all, clippy::pedantic)]
+
+#[must_use]
+pub fn part2(_input: &str) -> String {
+    "Not Finished".to_string()
+}
+
+#[cfg(test)]
+mod test {
+    use super::*;
+
+    const INPUT: &str = "";
+
+    #[test]
+    fn part2_works() {
+        let result = part2(INPUT);
+        assert_eq!(result, "Not Finished".to_string());
+    }
+}