From 8a2d7323ada56c5d00ece428c98efcb37edd2104 Mon Sep 17 00:00:00 2001
From: Kirill Kleymenov <k.kelolov@gmail.com>
Date: Mon, 23 Dec 2024 12:08:07 +0300
Subject: [PATCH] 23 ok

---
 data/examples/23.txt |  32 +++++++++++
 src/bin/23.rs        | 124 +++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 156 insertions(+)
 create mode 100644 data/examples/23.txt
 create mode 100644 src/bin/23.rs

diff --git a/data/examples/23.txt b/data/examples/23.txt
new file mode 100644
index 0000000..d8576a8
--- /dev/null
+++ b/data/examples/23.txt
@@ -0,0 +1,32 @@
+kh-tc
+qp-kh
+de-cg
+ka-co
+yn-aq
+qp-ub
+cg-tb
+vc-aq
+tb-ka
+wh-tc
+yn-cg
+kh-ub
+ta-co
+de-co
+tc-td
+tb-wq
+wh-td
+ta-ka
+td-qp
+aq-cg
+wq-ub
+ub-vc
+de-ta
+wq-aq
+wq-vc
+wh-yn
+ka-de
+kh-ta
+co-tc
+wh-qp
+tb-vc
+td-yn
\ No newline at end of file
diff --git a/src/bin/23.rs b/src/bin/23.rs
new file mode 100644
index 0000000..c4a3592
--- /dev/null
+++ b/src/bin/23.rs
@@ -0,0 +1,124 @@
+use std::collections::{HashMap, HashSet};
+
+advent_of_code::solution!(23);
+
+fn build_computers(input: &str) -> HashMap<String, HashSet<String>> {
+    let mut computers: HashMap<String, HashSet<String>> = HashMap::new();
+
+    for line in input.lines() {
+        let (left, right) = line.split_once("-").unwrap();
+
+        let ll = computers.entry(left.to_string()).or_insert(HashSet::new());
+        ll.insert(right.to_string());
+
+        let rr = computers.entry(right.to_string()).or_insert(HashSet::new());
+        rr.insert(left.to_string());
+    }
+    computers
+}
+
+pub fn part_one(input: &str) -> Option<u32> {
+    let computers = build_computers(input);
+    let mut triplets: HashSet<String> = HashSet::new();
+
+    for comp in computers.keys() {
+        if !comp.starts_with('t') {
+            continue;
+        }
+
+        let my_connections = computers.get(comp).unwrap();
+
+        for conn1 in my_connections.iter() {
+            if conn1 == comp {
+                continue;
+            }
+
+            let c1c = computers.get(conn1).unwrap();
+
+            for conn2 in my_connections.iter() {
+                if conn2 == comp || conn2 == conn1 {
+                    continue;
+                }
+
+                if c1c.contains(conn2) {
+                    let mut connvec: Vec<String> = vec![comp.clone(), conn1.clone(), conn2.clone()];
+                    connvec.sort();
+
+                    triplets.insert(connvec.join(","));
+                }
+            }
+        }
+    }
+
+    Some(triplets.len() as u32)
+}
+
+fn bron_kerbosch(
+    current: &mut HashSet<String>,
+    candidates: HashSet<String>,
+    excluded: HashSet<String>,
+    graph: &HashMap<String, HashSet<String>>,
+    max_clique: &mut HashSet<String>,
+) {
+    if candidates.is_empty() && excluded.is_empty() {
+        if current.len() > max_clique.len() {
+            max_clique.clear();
+            max_clique.extend(current.iter().cloned());
+        }
+        return;
+    }
+
+    let mut c_c = candidates.clone();
+    for v in candidates {
+        let conns = match graph.get(&v) {
+            Some(v) => v,
+            None => &HashSet::new(),
+        };
+
+        current.insert(v.clone());
+
+        let n_cand: HashSet<_> = c_c.intersection(conns).cloned().collect();
+        let n_ex: HashSet<_> = excluded.intersection(conns).cloned().collect();
+
+        bron_kerbosch(current, n_cand, n_ex, graph, max_clique);
+
+        current.remove(&v);
+        c_c.remove(&v);
+    }
+}
+
+pub fn part_two(input: &str) -> Option<String> {
+    let computers = build_computers(input);
+
+    let mut max_clique: HashSet<String> = HashSet::new();
+
+    bron_kerbosch(
+        &mut HashSet::new(),
+        computers.keys().cloned().collect(),
+        HashSet::new(),
+        &computers,
+        &mut max_clique,
+    );
+
+    let mut vectorized: Vec<String> = max_clique.iter().map(|v| v.clone()).collect();
+    vectorized.sort();
+
+    Some(vectorized.join(","))
+}
+
+#[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(7));
+    }
+
+    #[test]
+    fn test_part_two() {
+        let result = part_two(&advent_of_code::template::read_file("examples", DAY));
+        assert_eq!(result, Some("co,de,ka,ta".to_string()));
+    }
+}