[2023] Complete day 25

README.md

@@ -29,6 +29,7 @@ Thank you to [Eric Wastl](http://was.tl) for running this incredible yearly even
 - [Day 22: Sand Slabs](aoc_2023/src/day_22.rs)
 - [Day 23: A Long Walk](aoc_2023/src/day_23.rs)
 - [Day 24: Never Tell Me The Odds](aoc_2023/src/day_24.rs)
+- [Day 25: Snowverload](aoc_2023/src/day_25.rs)
 <!-- MARKER -->
 
 ## [2022](https://adventofcode.com/2022) [![aoc_2022](https://github.com/Basicprogrammer10/advent-of-code/actions/workflows/aoc_2022.yml/badge.svg)](https://github.com/Basicprogrammer10/advent-of-code/actions/workflows/aoc_2022.yml)

aoc_2023/Cargo.toml

@@ -14,3 +14,4 @@ once_cell = "1.18.0"
 polynomial = "0.2.6"
 rayon = "1.8.0"
 regex = "1.10.2"
+rustworkx-core = "0.13.2"

aoc_2023/src/day_25.rs

@@ -0,0 +1,83 @@
+use std::collections::HashMap;
+
+use common::{Answer, Solution};
+use rustworkx_core::{
+    connectivity::stoer_wagner_min_cut,
+    petgraph::{graph::UnGraph, Graph, Undirected},
+};
+
+pub struct Day25;
+
+impl Solution for Day25 {
+    fn name(&self) -> &'static str {
+        "Snowverload"
+    }
+
+    fn part_a(&self, input: &str) -> Answer {
+        let wires = parse(input);
+
+        let total = wires.wire.node_count();
+        let (len, side) = stoer_wagner_min_cut(&wires.wire, |_| Ok::<i32, ()>(1))
+            .unwrap()
+            .unwrap();
+
+        assert_eq!(len, 3);
+        ((total - side.len()) * side.len()).into()
+    }
+
+    fn part_b(&self, _input: &str) -> Answer {
+        Answer::Unimplemented
+    }
+}
+
+struct Wires<'a> {
+    wire: Graph<&'a str, (), Undirected>,
+}
+
+fn parse(input: &str) -> Wires {
+    let mut wire = UnGraph::new_undirected();
+
+    let mut nodes = HashMap::new();
+
+    for line in input.lines() {
+        let mut parts = line.split(": ");
+        let key = parts.next().unwrap();
+        let values = parts.next().unwrap().split_whitespace();
+
+        let node = *nodes.entry(key).or_insert_with(|| wire.add_node(key));
+        for value in values {
+            let value = *nodes.entry(value).or_insert_with(|| wire.add_node(value));
+            wire.add_edge(node, value, ());
+        }
+    }
+    Wires { wire }
+}
+
+#[cfg(test)]
+mod test {
+    use common::Solution;
+    use indoc::indoc;
+
+    use super::Day25;
+
+    const CASE: &str = indoc! {"
+        jqt: rhn xhk nvd
+        rsh: frs pzl lsr
+        xhk: hfx
+        cmg: qnr nvd lhk bvb
+        rhn: xhk bvb hfx
+        bvb: xhk hfx
+        pzl: lsr hfx nvd
+        qnr: nvd
+        ntq: jqt hfx bvb xhk
+        nvd: lhk
+        lsr: lhk
+        rzs: qnr cmg lsr rsh
+        frs: qnr lhk lsr
+    "};
+
+    #[test]
+    fn part_a() {
+        assert_eq!(Day25.part_a(CASE), 54.into());
+    }
+}

aoc_2023/src/lib.rs

@@ -26,6 +26,7 @@ mod day_21;
 mod day_22;
 mod day_23;
 mod day_24;
+mod day_25;
 // [import_marker]
 
 #[rustfmt::skip]
@@ -54,5 +55,6 @@ pub const ALL: &[&dyn Solution] = &[
     &day_22::Day22,
     &day_23::Day23,
     &day_24::Day24,
+    &day_25::Day25,
     // [list_marker]
 ];