wip: day 20

src/bin/20.rs

@@ -0,0 +1,117 @@
+use std::{collections::HashMap, str::FromStr};
+
+#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
+enum Module {
+    Broadcaster,
+    FlipFlop,
+    Conjuction,
+}
+
+#[derive(Debug)]
+struct ParseModuleError;
+
+impl FromStr for Module {
+    type Err = ParseModuleError;
+    fn from_str(s: &str) -> Result<Self, Self::Err> {
+        Ok(match s {
+            "%" => Module::FlipFlop,
+            "&" => Module::Conjuction,
+            _ => Module::Broadcaster,
+        })
+    }
+}
+
+#[derive(Debug)]
+struct Location {
+    module: Module,
+    inputs: HashMap<String, Option<bool>>,
+    outputs: Vec<String>,
+}
+
+fn parse_input(input: &str) -> (Vec<Location>, HashMap<String, usize>) {
+    let mut locations = Vec::new();
+    let mut mapper: HashMap<String, usize> = HashMap::new();
+
+    for line in input.lines() {
+        let (from, to) = line.split_once(" -> ").unwrap();
+        let (module, mut name) = from.split_at(1);
+        let module: Module = module.parse().unwrap();
+        if module == Module::Broadcaster {
+            name = from;
+        }
+
+        let l = Location {
+            module,
+            inputs: HashMap::new(),
+            outputs: to.split(", ").map(String::from).collect(),
+        };
+
+        locations.push(l);
+        *mapper.entry(name.to_string()).or_default() = locations.len() - 1;
+    }
+    for line in input.lines() {
+        let (from, to) = line.split_once(" -> ").unwrap();
+        let (_, name) = from.split_at(1);
+
+        for destination in to.split(", ") {
+            let index = mapper[name];
+            locations[index]
+                .inputs
+                .entry(destination.to_string())
+                .or_default();
+        }
+    }
+
+    (locations, mapper)
+}
+
+pub fn part_one(input: &str) -> Option<usize> {
+    let (locations, mapper) = parse_input(input);
+
+    let mut high = 0;
+    let mut low = 0;
+
+    for _ in 0..1000 {
+        let mut stack = vec!["broadcaster".to_string()];
+        while !stack.is_empty() {
+            let mut new_stack = Vec::new();
+
+            while let Some(s) = stack.pop() {
+                let index = mapper[&s];
+                let loc = &locations[index];
+
+                match loc.module {
+                    Module::Broadcaster => {
+                        for dest in loc.outputs.iter() {
+                            let index = mapper[dest];
+                            let loc = &locations[index];
+                        }
+                    }
+                }
+            }
+
+            stack = new_stack;
+        }
+    }
+
+    Some(high * low)
+}
+
+pub fn part_two(input: &str) -> Option<u32> {
+    None
+}
+
+aoc::solution!(20);
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    #[test]
+    fn test_part_one() {
+        assert_eq!(part_one(&aoc::template::read_file("examples", 20)), None);
+    }
+    #[test]
+    fn test_part_two() {
+        assert_eq!(part_two(&aoc::template::read_file("examples", 20)), None);
+    }
+}