do part 2

2024/src/day23.clj

@@ -1,8 +1,8 @@
 (ns day23
   (:require
-   [clojure.math :as math]
    [clojure.math.combinatorics :as combo]
-   [clojure.string :as s]
+   [clojure.set :as set]
+   [clojure.string :as str]
    [core :as c :refer :all]
    [input-manager :as i]))
 
@@ -17,7 +17,7 @@
                 flatten
                 set))
 
-;; part 1
+;; part 1, find interconncceted combos of 3 with nodes with at least one like #"t.*"
 (def part-1-ans
   (future
     (->> (combo/combinations edges 2)
@@ -33,12 +33,36 @@
          (map set)
          set
          count)))
-(future
+
+(comment
+
+  (future
     (println "processing part 1...")
     (println "part 1 answer:" @part-1-ans))
 
-(comment
   (realized? part-1-ans)
   (deref part-1-ans 0 "still processing")
   @part-1-ans)
 
+(defn make-graph [nodes edges]
+  (reduce (fn [graph el]
+            (assoc graph el (->> (filter #(contains? % el) edges)
+                                 (map #(disj % el))
+                                 (map first)
+                                 (set))))
+          {}
+          nodes))
+
+(def graph (make-graph nodes edges))
+
+;; part 2, find largest interconnected subgraph
+(->> (for [guess (->> graph
+                      (map reverse)
+                      (map (partial apply conj)))
+           part (combo/combinations (seq guess) 1)]
+       (reduce set/intersection
+               (map #(apply sorted-set (conj (graph %) %))
+                    (apply disj guess part))))
+     (filter (compose count #(> % 1)))
+     (map (partial str/join ","))
+     (apply max-key (compose (partial filter #(= \, %)) count)))