2015: d09: ex1: add solution

2015/d09/ex1/ex1.py

@@ -0,0 +1,34 @@
+#!/usr/bin/env python
+
+import collections
+import itertools
+import sys
+
+
+def solve(input: str) -> int:
+    def parse_line(input: str) -> tuple[str, str, int]:
+        p1, _, p2, _, dist = input.split()
+        return p1, p2, int(dist)
+
+    def parse(input: str) -> dict[str, dict[str, int]]:
+        res: dict[str, dict[str, int]] = collections.defaultdict(dict)
+        for p1, p2, dist in map(parse_line, input.splitlines()):
+            res[p1][p2] = dist
+            res[p2][p1] = dist
+        return res
+
+    # Boring Traveling Salesman solution
+    distances = parse(input)
+    return min(
+        sum(distances[s][e] for s, e in itertools.pairwise(travel_plan))
+        for travel_plan in itertools.permutations(distances.keys())
+    )
+
+
+def main() -> None:
+    input = sys.stdin.read()
+    print(solve(input))
+
+
+if __name__ == "__main__":
+    main()