Day 6 part 1 reimplemented with a directed graph
Using petgraph crate.
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parent
c71ca99eaa
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26
day6/Cargo.lock
generated
26
day6/Cargo.lock
generated
@ -3,4 +3,30 @@
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[[package]]
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name = "day6"
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version = "0.1.0"
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dependencies = [
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"petgraph 0.4.13 (registry+https://github.com/rust-lang/crates.io-index)",
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]
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[[package]]
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name = "fixedbitset"
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version = "0.1.9"
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source = "registry+https://github.com/rust-lang/crates.io-index"
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[[package]]
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name = "ordermap"
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version = "0.3.5"
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source = "registry+https://github.com/rust-lang/crates.io-index"
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[[package]]
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name = "petgraph"
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version = "0.4.13"
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source = "registry+https://github.com/rust-lang/crates.io-index"
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dependencies = [
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"fixedbitset 0.1.9 (registry+https://github.com/rust-lang/crates.io-index)",
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"ordermap 0.3.5 (registry+https://github.com/rust-lang/crates.io-index)",
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]
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[metadata]
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"checksum fixedbitset 0.1.9 (registry+https://github.com/rust-lang/crates.io-index)" = "86d4de0081402f5e88cdac65c8dcdcc73118c1a7a465e2a05f0da05843a8ea33"
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"checksum ordermap 0.3.5 (registry+https://github.com/rust-lang/crates.io-index)" = "a86ed3f5f244b372d6b1a00b72ef7f8876d0bc6a78a4c9985c53614041512063"
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"checksum petgraph 0.4.13 (registry+https://github.com/rust-lang/crates.io-index)" = "9c3659d1ee90221741f65dd128d9998311b0e40c5d3c23a62445938214abce4f"
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@ -7,3 +7,4 @@ edition = "2018"
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# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
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[dependencies]
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petgraph = "0.4.13"
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103
day6/src/main.rs
103
day6/src/main.rs
@ -4,14 +4,23 @@ use std::fs::File;
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use std::io::{prelude::*, BufReader};
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use std::result;
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use petgraph::graph::NodeIndex;
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use petgraph::{Direction, Graph};
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const INPUT: &str = "input/input.txt";
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type Result<T> = result::Result<T, Box<dyn Error>>;
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fn read_orbit_map(filename: &str) -> Result<HashMap<String, Option<String>>> {
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struct OrbitMap {
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graph: Graph<String, ()>,
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map: HashMap<String, NodeIndex>,
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}
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fn read_orbit_map(filename: &str) -> Result<OrbitMap> {
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let file = File::open(filename)?;
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let reader = BufReader::new(file);
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let mut objects: HashMap<String, Option<String>> = HashMap::new();
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let mut graph = Graph::<String, ()>::new();
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let mut map: HashMap<String, NodeIndex> = HashMap::new();
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for line in reader.lines() {
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let line = line?;
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@ -25,28 +34,44 @@ fn read_orbit_map(filename: &str) -> Result<HashMap<String, Option<String>>> {
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.expect("Invalid line, no orbiter part.")
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.to_string();
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objects.entry(mass_name.clone()).or_insert(None);
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objects.insert(orbiter_name.clone(), Some(mass_name));
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let mass_index = match map.get(&mass_name) {
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None => {
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let index = graph.add_node(mass_name.clone());
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map.insert(mass_name, index);
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index
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}
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Some(index) => *index,
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};
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let orbiter_index = match map.get(&orbiter_name) {
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None => {
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let index = graph.add_node(orbiter_name.clone());
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map.insert(orbiter_name, index);
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index
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}
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Some(index) => *index,
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};
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graph.update_edge(orbiter_index, mass_index, ());
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}
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Ok(objects)
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Ok(OrbitMap { graph, map })
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}
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fn get_orbit_count(orbit_map: &HashMap<String, Option<String>>, orbiter: String) -> u32 {
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match orbit_map.get(&orbiter) {
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None => panic!("Incomplete orbit map"),
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Some(mass) => match mass {
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None => return 0,
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Some(mass) => return 1 + get_orbit_count(orbit_map, mass.to_string()),
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},
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fn get_orbit_count(orbit_map: &OrbitMap, orbiter: NodeIndex) -> u32 {
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for neighbor in orbit_map
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.graph
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.neighbors_directed(orbiter, Direction::Outgoing)
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{
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return 1 + get_orbit_count(orbit_map, neighbor);
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}
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return 0;
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}
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fn get_orbit_count_checksum(orbit_map: &HashMap<String, Option<String>>) -> u32 {
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fn get_orbit_count_checksum(orbit_map: &OrbitMap) -> u32 {
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let mut checksum = 0;
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for orbiter in orbit_map.keys() {
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checksum += get_orbit_count(&orbit_map, orbiter.to_string());
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for orbiter in orbit_map.map.keys() {
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let node = orbit_map.map.get(orbiter).expect("Incomplete orbit map");
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checksum += get_orbit_count(&orbit_map, *node);
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}
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checksum
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@ -58,6 +83,11 @@ fn solve_part1() -> Result<u32> {
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}
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fn solve_part2() -> Result<i32> {
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let orbit_map = read_orbit_map(INPUT)?;
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let you = orbit_map.map.get("YOU").expect("YOU not found in orbit map");
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let san = orbit_map.map.get("SAN").expect("SAN not found in orbit map");
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// let mut bfs = Bfs::new(&orbit_map.graph, *you);
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// that BFS doesn't tell me the edges from node for each iteration. guess I'll roll my own
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Ok(0)
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}
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@ -76,26 +106,31 @@ mod tests {
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#[test]
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fn reads_orbit_map() {
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let orbit_map = read_orbit_map(TEST_INPUT).unwrap();
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assert_eq!(
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read_orbit_map(TEST_INPUT).unwrap(),
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[
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("COM".to_string(), None),
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("B".to_string(), Some("COM".to_string())),
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("C".to_string(), Some("B".to_string())),
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("D".to_string(), Some("C".to_string())),
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("E".to_string(), Some("D".to_string())),
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("F".to_string(), Some("E".to_string())),
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("G".to_string(), Some("B".to_string())),
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("H".to_string(), Some("G".to_string())),
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("I".to_string(), Some("D".to_string())),
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("J".to_string(), Some("E".to_string())),
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("K".to_string(), Some("J".to_string())),
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("L".to_string(), Some("K".to_string())),
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]
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.iter()
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.cloned()
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.collect()
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);
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format!("{:?}", orbit_map.graph),
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"Graph { \
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Ty: \"Directed\", \
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node_count: 12, \
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edge_count: 11, \
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edges: (1, 0), (2, 1), (3, 2), (4, 3), (5, 4), (6, 1), (7, 6), \
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(8, 3), (9, 4), (10, 9), (11, 10), \
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node weights: {\
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0: \"COM\", \
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1: \"B\", \
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2: \"C\", \
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3: \"D\", \
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4: \"E\", \
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5: \"F\", \
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6: \"G\", \
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7: \"H\", \
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8: \"I\", \
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9: \"J\", \
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10: \"K\", \
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11: \"L\"\
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} \
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}",
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)
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}
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#[test]
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