day 25

Cargo.toml

@@ -33,3 +33,4 @@ itertools = "0.12.0"
 num = "0.4.1"
 ndarray = "0.15.6"
 ndarray-linalg = { version = "0.16", features = ["openblas-static"] }
+rustworkx-core = "0.13.2"

README.md

@@ -64,8 +64,9 @@ Solutions for [Advent of Code](https://adventofcode.com/) in [Rust](https://www.
 | [Day 22](./src/bin/22.rs) | `9.5ms` | `17.6ms` |
 | [Day 23](./src/bin/23.rs) | `2.3ms` | `1.7s` |
 | [Day 24](./src/bin/24.rs) | `20.1ms` | `154.2µs` |
+| [Day 25](./src/bin/25.rs) | `380.2ms` | `-` |
 
-**Total: 48331.47ms**
+**Total: 48711.67ms**
 <!--- benchmarking table --->
 
 ---

src/bin/25.rs

@@ -0,0 +1,70 @@
+use std::convert::Infallible;
+use std::collections::HashMap;
+use rustworkx_core::connectivity::stoer_wagner_min_cut;
+use rustworkx_core::petgraph::Undirected;
+use rustworkx_core::petgraph::csr::Csr;
+
+advent_of_code::solution!(25);
+
+type Graph<'a> = Csr<&'a str, (), Undirected>;
+
+fn parse_wiring(input: &str) -> (&str, Vec<&str>) {
+    let (key, wires) = input.split_once(": ").unwrap();
+    (key, wires.split_ascii_whitespace().collect())
+}
+
+fn parse(input: &str) -> Graph {
+    let wires = input.lines()
+                     .map(|l| parse_wiring(l))
+                     .collect::<Vec<_>>();
+
+    let mut nodes: HashMap<&str, u32> = HashMap::new();
+    let mut graph = Csr::new();
+
+    for (wire, _) in wires.iter() {
+        nodes.insert(wire, graph.add_node(*wire));
+    }
+
+    for (wire, conns) in wires {
+        let wire_idx = nodes[wire];
+
+        for conn in conns {
+            let conn_idx = nodes.entry(conn).or_insert_with(|| graph.add_node(conn));
+            graph.add_edge(wire_idx, *conn_idx, ());
+        }
+    }
+
+    graph
+}
+
+pub fn part_one(input: &str) -> Option<u32> {
+    let graph = parse(input);
+
+    let (_, connected_set) = stoer_wagner_min_cut(&graph, |_| Ok::<i32, Infallible>(1)).unwrap().unwrap();
+
+    let size1 = connected_set.len();
+    let size2 = graph.node_count() - size1;
+
+    Some((size1 * size2) as u32)
+}
+
+pub fn part_two(_input: &str) -> Option<u32> {
+    None
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_part_one() {
+        let result = part_one(&advent_of_code::template::read_file("examples", DAY));
+        assert_eq!(result, Some(54));
+    }
+
+    #[test]
+    fn test_part_two() {
+        let result = part_two(&advent_of_code::template::read_file("examples", DAY));
+        assert_eq!(result, None);
+    }
+}