Implement breadth-first search to solve vault

notes.md

@@ -47,7 +47,7 @@ At the foothills, the first area of the RPG:
 Required opcodes: All except `halt`
 
 ### Code 5 (Twisty passages)
-After falling down the bridge, there is an `empty lantern` to the `east`, which should be `take`n. To the `west`, there is a passage, where one can take the `ladder` down or venture into the `darkness`. Attempting to venture into the `darkness` at this point will result in being eaten by Grues.
+After falling down the bridge, there is an `empty lantern` to the `east`, which should be `take`n. To the `west`, there is a `passage`, where one can take the `ladder` down or venture into the `darkness`. Attempting to venture into the `darkness` at this point will result in being eaten by Grues.
 
 Taking the `ladder` down, then traversing `west`, `south`, `north`, a code is obtained:
 
@@ -60,7 +60,7 @@ Taking the `ladder` down, then traversing `west`, `south`, `north`, a code is ob
 There is also a can, which can be `take`n and `use`d to fill the lantern, which can then be `use`d to become lit, and which will keep away Grues.
 
 ### Code 6 (Dark passage, ruins and teleporter)
-Returning to the fork at the passage and venturing to the `darkness`, we now `continue` `west`ward to the ruins. The `north` door is locked, but dotted elsewhere around the ruins are a `red coin` (2 dots), `corroded coin` (triangle = 3 sides), `shiny coin` (pentagon = 5 sides), `concave coin` (7 dots) and `blue coin` (9 dots) which should be `take`n and `look`ed at, and the equation:
+Returning to the fork at the passage and venturing to the `darkness`, we now `continue` `west`ward several times, then `north`ward several times to the ruins. The `north` door is locked, but dotted elsewhere around the ruins are a `red coin` (2 dots), `corroded coin` (triangle = 3 sides), `shiny coin` (pentagon = 5 sides), `concave coin` (7 dots) and `blue coin` (9 dots) which should be `take`n and `look`ed at, and the equation:
 
     _ + _ * _^2 + _^3 - _ = 399
 
@@ -248,7 +248,7 @@ I've implemented this as a debug function to prepare the teleporter:
 ### Code 8 (Beach and vault)
 Arriving at the beach, traverse `north`ward until you reach a fork. To the `east` lies a `journal` containing clues as to the upcoming puzzle.
 
-With the ability to map the puzzle (possibly with the help of our knowledge of the map data format), and (unlike the adventurers, it seems) a grasp of basic arithmetic, this puzzle shouldn't be too difficult to solve. I couldn't do better than [paiv](https://github.com/paiv)'s [solution](https://paiv.github.io/blog/2016/04/24/synacor-challenge.html) ([code](https://github.com/paiv/synacor-challenge/tree/master/code/src/vault), [map](https://github.com/paiv/synacor-challenge/blob/master/notes/vault-locks.svg)), and it doesn't look like there's much parallelisation to do, so I'll leave you with those links.
+With the ability to map the puzzle (possibly with the help of our knowledge of the map data format), and (unlike the adventurers, it seems) a grasp of basic arithmetic, this puzzle shouldn't be too difficult to solve. Armed with our map data, we can now do a [breadth-first search to find the shortest solution](https://github.com/RunasSudo/synacor.py/blob/master/tools/bfs.py).
 
 The solution is:
 

tools/bfs.py

@@ -0,0 +1,155 @@
+#!/usr/bin/env python3
+#    synacor.py - An implementation of the Synacor Challenge
+#    Copyright © 2017  RunasSudo
+#
+#    This program is free software: you can redistribute it and/or modify
+#    it under the terms of the GNU Affero General Public License as published by
+#    the Free Software Foundation, either version 3 of the License, or
+#    (at your option) any later version.
+#
+#    This program is distributed in the hope that it will be useful,
+#    but WITHOUT ANY WARRANTY; without even the implied warranty of
+#    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+#    GNU Affero General Public License for more details.
+#
+#    You should have received a copy of the GNU Affero General Public License
+#    along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+import collections
+import re
+import struct
+import sys
+
+rooms = {}
+
+class Door:
+	def __init__(self):
+		self.name = None
+		self.destination = None
+
+class Room:
+	def __init__(self):
+		self.location = None
+		self.name = None
+		self.description = None
+		self.doors = []
+		self.callback = None
+		
+		self.is_operator = False
+		self.mutate_value = None
+
+# Read code into memory
+SYN_MEM = [0] * 32768
+
+with open('../dumps/init.raw', 'rb') as data:
+	i = 0
+	while True:
+		byteData = data.read(2)
+		if len(byteData) < 2:
+			break
+		SYN_MEM[i] = struct.unpack('<H', byteData)[0]
+		i += 1
+
+def traverse_room(location):
+	if location in rooms:
+		return
+	
+	# Read data from initial struct
+	ptr_name = SYN_MEM[location]
+	ptr_description = SYN_MEM[location + 1]
+	ptr_door_names = SYN_MEM[location + 2]
+	ptr_door_dests = SYN_MEM[location + 3]
+	ptr_callback = SYN_MEM[location + 4]
+	
+	room = Room()
+	room.location = location
+	
+	# Name
+	len_name = SYN_MEM[ptr_name]
+	room.name = bytes(SYN_MEM[ptr_name+1:ptr_name+1+len_name]).decode('ascii')
+	
+	if room.name.startswith('Vault '):
+		rooms[location] = room
+	else:
+		return
+	
+	# Description
+	len_description = SYN_MEM[ptr_description]
+	room.description = bytes(SYN_MEM[ptr_description+1:ptr_description+1+len_description]).decode('ascii')
+	
+	# Callback
+	room.callback = ptr_callback
+	
+	# Door names
+	door_name_ptrs = []
+	len_door_name_ptrs = SYN_MEM[ptr_door_names]
+	door_name_ptrs = SYN_MEM[ptr_door_names+1:ptr_door_names+1+len_door_name_ptrs]
+	
+	# Door dests
+	door_dests = []
+	len_door_dest_ptrs = SYN_MEM[ptr_door_dests]
+	door_dest_ptrs = SYN_MEM[ptr_door_dests+1:ptr_door_dests+1+len_door_dest_ptrs]
+	
+	assert len(door_name_ptrs) == len(door_dest_ptrs)
+	
+	# Process doors
+	for i in range(len(door_name_ptrs)):
+		door = Door()
+		
+		len_door_name = SYN_MEM[door_name_ptrs[i]]
+		door.name = bytes(SYN_MEM[door_name_ptrs[i]+1:door_name_ptrs[i]+1+len_door_name]).decode('ascii')
+		
+		door.destination = door_dest_ptrs[i]
+		
+		room.doors.append(door)
+	
+	# Parse description
+	if room.name == 'Vault Antechamber':
+		room.mutate_value = lambda val: '22'
+	else:
+		match = re.search(r"mosaic depicting the number '(.*)'", room.description)
+		if match:
+			room_value = match.group(1)
+			room.mutate_value = lambda val: val + room_value + ')'
+		else:
+			match = re.search(r"mosaic depicting a '(.*)' symbol", room.description)
+			if match:
+				room.is_operator = True
+				room_operator = match.group(1)
+				room.mutate_value = lambda val: '(' + val + room_operator
+			else:
+				raise Exception('Unable to parse description: {}'.format(room.description))
+	
+	for door in room.doors:
+		traverse_room(door.destination)
+
+# Seed rooms
+traverse_room(0x0a3f)
+
+# Breadth-first search
+
+queue = collections.deque()
+initial_status = ([(None, 0x0a3f)], None) # current path, previous value
+queue.append(initial_status)
+
+while True:
+	current_status = queue.popleft()
+	current_room = current_status[0][-1][1]
+	current_value = rooms[current_room].mutate_value(current_status[1])
+	
+	print(current_status)
+	print(current_value)
+	
+	if current_room == 0x0a12: # Vault Door
+		if eval(current_value) == 30:
+			# We have reached the goal
+			sys.exit(0)
+		else:
+			# We must not enter the vault door unless we have the right number, else the orb will disappear
+			# Do not continue this line of searching
+			continue
+	
+	for edge in rooms[current_room].doors:
+		if edge.destination in rooms:
+			new_status = (current_status[0] + [(edge.name, edge.destination)], current_value)
+			queue.append(new_status)

tools/graph.py

@@ -168,7 +168,7 @@ def traverse_item(location):
 # Seed rooms
 traverse_room(0x090d) # Foothills
 traverse_room(0x09b8) # Synacor Headquarters
-traverse_room(0x09cc) # Beachside
+traverse_room(0x09c2) # Beachside
 
 # Exhaustive check
 for i in range(0x090d, 0x099e, 5):