wip: part 1 debugging

data/examples/20.txt

@@ -0,0 +1,5 @@
+broadcaster -> a, b, c
+%a -> b
+%b -> c
+%c -> inv
+&inv -> a

src/bin/20.rs

@@ -1,9 +1,14 @@
-use std::{collections::HashMap, str::FromStr};
+use std::{
+    collections::{HashMap, VecDeque},
+    mem::swap,
+    process::Output,
+    str::FromStr,
+};
 
 #[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
 enum Module {
     Broadcaster,
-    FlipFlop,
+    FlipFlop(bool),
     Conjuction,
 }
 
@@ -14,7 +19,7 @@ impl FromStr for Module {
     type Err = ParseModuleError;
     fn from_str(s: &str) -> Result<Self, Self::Err> {
         Ok(match s {
-            "%" => Module::FlipFlop,
+            "%" => Module::FlipFlop(false),
             "&" => Module::Conjuction,
             _ => Module::Broadcaster,
         })
@@ -22,16 +27,37 @@ impl FromStr for Module {
 }
 
 #[derive(Debug)]
-struct Location {
+struct Node {
+    index: usize,
     module: Module,
-    inputs: HashMap<String, Option<bool>>,
-    outputs: Vec<String>,
+    inputs: Vec<usize>,
+    outputs: Vec<usize>,
 }
 
-fn parse_input(input: &str) -> (Vec<Location>, HashMap<String, usize>) {
-    let mut locations = Vec::new();
+fn parse_input(input: &str) -> Vec<Node> {
+    let mut nodes = Vec::new();
     let mut mapper: HashMap<String, usize> = HashMap::new();
 
+    for line in input.lines() {
+        let (from, _) = line.split_once(" -> ").unwrap();
+        let (module, mut name) = from.split_at(1);
+        let module: Module = module.parse().unwrap();
+        if module == Module::Broadcaster {
+            name = from;
+        }
+
+        *mapper.entry(name.to_string()).or_default() = nodes.len();
+
+        let l = Node {
+            module,
+            index: nodes.len(),
+            inputs: Vec::new(),
+            outputs: Vec::new(),
+        };
+
+        nodes.push(l);
+    }
+
     for line in input.lines() {
         let (from, to) = line.split_once(" -> ").unwrap();
         let (module, mut name) = from.split_at(1);
@@ -40,53 +66,96 @@ fn parse_input(input: &str) -> (Vec<Location>, HashMap<String, usize>) {
             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();
+        for destination in to.split(", ") {
+            let to_index = mapper[destination];
+            nodes[index].outputs.push(to_index);
+            nodes[to_index].inputs.push(index);
         }
     }
 
-    (locations, mapper)
+    nodes
 }
 
 pub fn part_one(input: &str) -> Option<usize> {
-    let (locations, mapper) = parse_input(input);
+    let mut nodes = parse_input(input);
 
-    let mut high = 0;
-    let mut low = 0;
+    let mut graph = vec![vec![None; input.len()]; input.len()];
+
+    let mut highs = 0;
+    let mut lows = 0;
+
+    let broadcaster = nodes
+        .iter()
+        .find(|x| x.module == Module::Broadcaster)?
+        .index;
 
     for _ in 0..1000 {
-        let mut stack = vec!["broadcaster".to_string()];
+        let mut stack = VecDeque::from([broadcaster]);
         while !stack.is_empty() {
-            let mut new_stack = Vec::new();
+            let mut new_stack = VecDeque::new();
 
-            while let Some(s) = stack.pop() {
-                let index = mapper[&s];
-                let loc = &locations[index];
+            while let Some(index) = stack.pop_front() {
+                let node = &nodes[index];
+                let mut new_module = None;
 
-                match loc.module {
+                match node.module {
                     Module::Broadcaster => {
-                        for dest in loc.outputs.iter() {
-                            let index = mapper[dest];
-                            let loc = &locations[index];
+                        for dest_index in node.outputs.iter() {
+                            graph[index][*dest_index] = Some(false);
+                            new_stack.push_back(*dest_index);
+                            lows += 1;
                         }
                     }
+                    Module::FlipFlop(high) => {
+                        let mut swapper = None;
+                        for in_index in nodes[index].inputs.iter() {
+                            let value = &mut graph[*in_index][index];
+                            if value.is_some() {
+                                debug_assert!(swapper.is_none());
+                                swap(&mut swapper, value);
+                            }
+                        }
+
+                        if !swapper.unwrap() {
+                            let signal = !high;
+
+                            for dest_index in nodes[index].outputs.iter() {
+                                graph[index][*dest_index] = Some(signal);
+                                new_stack.push_back(*dest_index);
+                                if signal {
+                                    highs += 1;
+                                } else {
+                                    lows += 1;
+                                }
+                            }
+
+                            new_module = Some(Module::FlipFlop(signal));
+                        }
+                    }
+                    Module::Conjuction => {
+                        let mut all = true;
+
+                        for in_index in nodes[index].inputs.iter() {
+                            let value = graph[*in_index][index];
+                            all &= value.unwrap_or(false);
+                        }
+
+                        for dest_index in nodes[index].outputs.iter() {
+                            graph[index][*dest_index] = Some(!all);
+                            new_stack.push_back(*dest_index);
+                            if !all {
+                                highs += 1;
+                            } else {
+                                lows += 1;
+                            }
+                        }
+                    }
+                }
+
+                let node = &mut nodes[index];
+                if let Some(module) = new_module {
+                    node.module = module;
                 }
             }
 
@@ -94,7 +163,7 @@ pub fn part_one(input: &str) -> Option<usize> {
         }
     }
 
-    Some(high * low)
+    Some(highs * lows)
 }
 
 pub fn part_two(input: &str) -> Option<u32> {