Optimized solution

src/Year_2015/P9.py

@@ -32,8 +32,6 @@
 from itertools import permutations
 
 import networkx as nx
-import networkx.algorithms.approximation as nx_app
-from networkx.classes.function import path_weight
 
 with open("files/P9.txt") as f:
     routes = [line for line in f.read().strip().split("\n")]
@@ -44,13 +42,10 @@ for route in routes:
     from_, to_ = cities.split(" to ")
     G.add_edge(from_, to_, weight=int(dist))
 
-cycle = nx_app.christofides(G, weight="weight")
-
 paths = []
-for f, t in permutations(cycle, 2):
-    for path in nx.all_simple_paths(G, source=f, target=t):
-        if len(path) == len(cycle) - 1:
-            paths.append(path_weight(G, path, weight="weight"))
+for route in permutations(G.nodes):
+    distance = sum(G[u][v]["weight"] for u, v in zip(route, route[1:]))
+    paths.append(distance)
 
 
 def part_1() -> None: