done with 2023

2023/day-25/src/part1.rs

@@ -0,0 +1,92 @@
+#![warn(clippy::all, clippy::pedantic)]
+
+use std::collections::HashMap;
+
+use itertools::Itertools;
+use nom::{
+    bytes::complete::tag,
+    character::complete,
+    multi::separated_list1,
+    sequence::{separated_pair, tuple},
+    IResult,
+};
+use petgraph::prelude::*;
+use rustworkx_core::connectivity::stoer_wagner_min_cut;
+
+/// day 25 part 1 of aoc 2023
+///
+/// # Arguments
+/// - input the input for today's puzzle
+///
+/// # Panics
+/// panics whne it cannot parse the input OR when ever the number of game numbers is greater than
+#[must_use]
+pub fn part1(input: &str) -> String {
+    let (_, initial_map) = parse_input(input).expect("AOC should have valid input");
+
+    let all_node_strings = initial_map
+        .iter()
+        .flat_map(|(key, nodes)| {
+            let mut nodes = nodes.clone();
+            nodes.push(key);
+            nodes
+        })
+        .unique()
+        .collect::<Vec<_>>();
+
+    let mut graph = UnGraph::<&str, u32>::default();
+    let node_map = all_node_strings
+        .iter()
+        .map(|&id| (id, graph.add_node(id)))
+        .collect::<HashMap<_, _>>();
+
+    for (&src_id, dest_nodes) in &initial_map {
+        for &dest_id in dest_nodes {
+            graph.add_edge(node_map[src_id], node_map[dest_id], 1);
+        }
+    }
+    let total_nodes = all_node_strings.len();
+    let min_cut_res: rustworkx_core::Result<Option<(usize, Vec<_>)>> =
+        stoer_wagner_min_cut(&graph, |_| Ok(1));
+    let (_mincut, partition) = min_cut_res.unwrap().unwrap();
+    let partition_len = partition.len();
+    let rest_len = total_nodes - partition_len;
+    (partition_len * rest_len).to_string()
+}
+
+fn parse_input(input: &str) -> IResult<&str, HashMap<&str, Vec<&str>>> {
+    let (input, nodes_as_array) = separated_list1(
+        complete::line_ending,
+        separated_pair(
+            complete::alpha1,
+            tuple((tag(":"), complete::space0)),
+            separated_list1(complete::space1, complete::alpha1),
+        ),
+    )(input)?;
+    Ok((input, nodes_as_array.into_iter().collect()))
+}
+
+#[cfg(test)]
+mod test {
+    use super::*;
+
+    const INPUT: &str = "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 part1_works() {
+        let result = part1(INPUT);
+        assert_eq!(result, "54".to_string());
+    }
+}