graph.py

#!/usr/bin/env python3
from functools import reduce

def append_to_graph(graph, elms):
    if len(elms) == 0:
        return graph
    el, *ms = elms
    if type(el) is str:
        return append_to_graph({**graph, **{el: set()}}, ms)
    e, l = el
    return append_to_graph({**graph, **{e: graph[e] | {l},
                                        l: graph[l] | {e}}},
                            ms)
def make_graph (*args):
    return append_to_graph({}, args)

def find_paths(graph, src, dest, path=[]):
    path = path + [src]
    if src == dest:
        return [path]
    if src not in graph:
        return []
    ## Sintaxe tosca do python não deixa eu quebrar linha ai fica essa merda longa
    return reduce(lambda p, edge: [*p, *find_paths(graph, edge, dest, path)] if edge not in path else p,
                  graph[src],
                  [])

graph = make_graph("a", "b", "c", "d", "e",
        ##         ^ nós (pessoas)
        ##         \/ relações (amizades)
                   {"a", "b"},
                   {"b", "c"},
                   {"b", "d"},
                   {"c", "d"},
                   {"a", "d"},
                   {"d", "e"})

menor, *outros = sorted(find_paths(graph, "a", "e"),
                        key=lambda x: len(x))

print({"menor": menor, "outros": outros})