#/usr/bin/env python

# Remove all instances of #"1"# from the code 
# to view Part 1 interactively

# Remove all instances of #"2"# from the code
# and comment out the one originally uncommented
# line under each instance of #"2"# (three such instances
# are present in this program) to run Part 1 rather
# than Part 2

# In the above instructions, #"x"# for some digit "x"
# (without quotes) represents #x# in the actual code
# below

pipes = []

with open("/home/login/bin/advent17/input24.txt") as f:
	for line in f:
		pipes.append([int(n) for n in line[:-1].split("/")])

def pipes_containing_connector(n, pipe_list):
	pipes_sublist = []
	for pipe in pipe_list:
		if n in pipe:
			pipes_sublist.append(pipe)
	return pipes_sublist

bridges = []
strengths = []
pipes_left = []
pipes_with_0_connector = pipes_containing_connector(0, pipes)
# set so that checking if element belongs in set
# has constant time complexity
for pipe in pipes_with_0_connector:
	bridges.append([[0],pipe])
	strengths.append(sum(pipe))
	pipes_left.append([p for p in pipes if p!=pipe])

connected_connector = open_connector = 0

# Legend: (Max Strength, min Strength, number of bridges)
#1#print("Ms, ms, nb")
#1#print("")
max_strength = max(strengths)
min_strength = min(strengths)
#2#while max_strength!=min_strength:
while bridges:
	bridge_indices = range(len(bridges))
	#1#print(max_strength, min_strength, len(bridges))
	#1#input()
	for i in bridge_indices:
		pipes_left = (p for p in pipes if p not in bridges[i])

		if not pipes_left: # empty generator is False
			continue

		# Current connected_connector is open_connector
		# from previous iteration
		connected_connector = open_connector
		
		# Setting current open_connector
		if bridges[i][-1][0] in bridges[i][-2]:
			open_connector = bridges[i][-1][1]
		elif bridges[i][-1][1] in bridges[i][-2]:
			open_connector = bridges[i][-1][0]

		connectable_pipes = pipes_containing_connector(open_connector, pipes_left)

		for pipe in connectable_pipes:
			my_bridge = [p for p in bridges[i]]
			my_bridge.append(pipe)
			my_strength = strengths[i]
			bridges.append(my_bridge)
			strengths.append(my_strength+sum(pipe))
	offset=0
	max_strength = max(strengths)
	min_strength = min(strengths)
	for i in bridge_indices:
		#2#if strengths[i-offset] < max_strength:
		#2#	del bridges[i-offset], strengths[i-offset]
		#2#	offset+=1
		del bridges[0], strengths[0]

#2#print("Part 1: " + str(max_strength))
print("Part 2: " + str(max_strength))