day9

day9.py

import itertools
from collections import defaultdict
dist = defaultdict(lambda: float('inf'))
cities = set()

with open('input9.txt') as f:
    for line in f:
        frags = line.strip().split()
        src_dest = frags[0], frags[2]
        dist[frozenset(src_dest)] = int(frags[4])
        cities.update(src_dest)

def distances():
    for perm in itertools.permutations(cities):
        yield sum(dist[frozenset(pair)] for pair in zip(perm, perm[1:]))

distances = list(distances())
print(min(distances))  # part one
print(max(distances))  # part two