Advent of Code 2024 day 23 part 1

from collections import defaultdict
from sys import argv


def parse(src):
    for line in src.splitlines():
        if line == '':
            continue
        first, second = line.split('-', 1)
        yield first.strip(), second.strip()


def make_graph(connections):
    graph = defaultdict(set)
    for first, second in connections:
        graph[first].add(second)
        graph[second].add(first)
    return graph


def find_triples(graph):
    triples = set()
    nodes = list(graph.keys())
    for index, a in enumerate(graph):
        for b in graph[a]:
            for c in nodes[index+1:]:
                if {a, b} <= graph[c]:
                    triples.add(frozenset((a, b, c)))
    return triples


def main(connections):
    total = 0
    graph = make_graph(connections)
    triples = find_triples(graph)
    for triple in triples:
        if any(x[0] == 't' for x in triple):
            total += 1
    return total


if __name__ == '__main__':
    print(main(parse(open(argv[1]).read())))