2023 day 25.

src/holt59/aoc/2023/day25.py

@@ -1,11 +1,27 @@
 import sys
 from collections import defaultdict
 from dataclasses import dataclass
+import networkx as nx
 
-lines = sys.stdin.read().splitlines()
+components = {
+    (p := line.split(": "))[0]: p[1].split() for line in sys.stdin.read().splitlines()
+}
+
+targets = {
+    t for c in components for t in components[c] if t not in components
+}
+
+G = nx.Graph()
+G.add_nodes_from(list(components) + list(targets))
+G.add_edges_from((u, v) for u, vs in components.items() for v in vs)
+
+cut = nx.minimum_edge_cut(G) 
+G.remove_edges_from(cut)
+
+c1, c2 = nx.connected_components(G)
 
 # part 1
-answer_1 = ...
+answer_1 = len(c1) * len(c2)
 print(f"answer 1 is {answer_1}")
 
 # part 2