from search import *
class BFSFrontier(Frontier):
“””Implements a frontier container appropriate for breadth-first
search.”””
def __init__(self):
“””The constructor takes no argument. It initialises the
container to an empty list.”””
self.container = []
def add(self, path):
self.container.append(path)
def __iter__(self):
while len(self.container) > 0:
yield self.container.pop(0)
class FunkyNumericGraph(Graph):
“””A graph where nodes are numbers. A node (number) n leads to n-1 and
n+2. Nodes that are divisible by 10 are goal nodes.”””
def __init__(self, starting_number):
self.starting_number = starting_number
def outgoing_arcs(self, tail_node):
yield Arc(tail_node, tail_node – 1, label=”1down”, cost=1)
yield Arc(tail_node, tail_node + 2, label=”2up”, cost=1)
def starting_nodes(self):
yield self.starting_number
def is_goal(self, node):
return node % 10 == 0
def main():
# Example 1
print()
graph = FunkyNumericGraph(4)
for node in graph.starting_nodes():
print(node)
# Example 2
print()
graph = FunkyNumericGraph(4)
for arc in graph.outgoing_arcs(7):
print(arc)
# Example 3
print()
graph = FunkyNumericGraph(3)
solutions = generic_search(graph, BFSFrontier())
print_actions(next(solutions))
print()
print_actions(next(solutions))
# Example 4
print()
from itertools import dropwhile
graph = FunkyNumericGraph(3)
solutions = generic_search(graph, BFSFrontier())
print_actions(next(dropwhile(lambda path: path[-1].head <= 10, solutions)))
if __name__ == "__main__":
main()