#!/usr/bin/env python
# encoding=utf-8 (pep 0263)
from linked_lists import LinkedList, Cons, Nil, member, member_anyX
def path(a, z, graph):
for cesta, cena in path1(a, LinkedList([z]), 0, graph, 1):
yield (cesta, cena)
def path1(a, akumulator_cesty, akumulator_ceny, graph, depth):
if akumulator_cesty.head == a:
yield (akumulator_cesty, akumulator_ceny)
else:
y = akumulator_cesty.head
for x, cenaXY in adjacent_anyXcenaXY(y, graph):
if not member(x, akumulator_cesty):
for cesta, cena in path1(a, Cons(x, akumulator_cesty),
akumulator_ceny + cenaXY, graph, depth+1):
yield (cesta, cena)
def adjacent_anyXcenaXY(y, edges):
for a, b, cenaAB in member_anyX(edges):
if y == a:
yield (b, cenaAB)
if y == b:
yield (a, cenaAB)
# demonstracni vypis
if __name__ == "__main__":
print('Cesta v grafu\n')
cesta_, cena_ = next(path("s", "u", LinkedList([
("s", "t", 3), ("t", "v", 1), ("t", "u", 5), ("u", "t", 2), ("v", "u", 2)])))
print('Cesta=%s' % cesta_)
print('Cena=%d\n' % cena_)