Connecting via netcat gives us
Hi there! Stupid CAPTCHA: enter your name, user40319
Entering the username gives us a bunch of mazes in this format…
layer (1, y, z): = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = =
This repeats from layer 0 to 49 or so, and then we are asked to find a path from any coordinate in this maze to another coordinate. This looks like a typical Association for Computing Machinery contest question, so I quickly ran over to programming team member Antony Stabile, Progrmaming Diety for the solution. Here’s the main logic from it, it’s a BFS algorithm that finds the shortest path:
Scanner in = new Scanner(new FileReader(new File("map.txt")));
PrintWriter out = new PrintWriter(new FileWriter(new File("map.out")));
ArrayList input = new ArrayList();
while(in.hasNext()) input.add(in.nextLine());
ySize = 1;
while(input.get(ySize).charAt(0)=='=') ySize++;
ySize--;
xSize = (input.size()-1)/(ySize+1);
zSize = (input.get(1).length())/2;
boolean[][][] g = new boolean[xSize][ySize][zSize]; // true if blocked
for(int i=0; i
Here's the shoddy python I wrote to handle it:
import socket
import re
import os
# Handle connection
s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
s.connect(("ctf.phdays.com", 1165))
# We log everything to a file
mapcount = 10
def logshit(stuff):
tempf = open("map%d.txt" % (mapcount), 'a')
tempf.write(stuff)
# Dump the map to a text file and run the compiled java class from earlier..
def gomap(mapstr):
f = open('map.txt', 'w')
f.write(mapstr)
f.close()
print "running generatorn"
os.system("java map")
print "sending shortest pathn"
shortestpath = open('map.out', 'r').read()
print shortestpath + "n"
s.sendall(shortestpath)
# parse/log captcha
data = s.recv(1024)
captcha_str = repr(data)
print 'Received:', captcha_str
# get user id
name_match = re.search(r'(d+)', captcha_str)
print name_match
# send captcha back
sendback = 'user%sn' % name_match.group(0)
print sendback
s.sendall(sendback)
# if we receive the chunk below, map is done being sent.
end_regex = re.compile('Find a path between.+:')
map_data = ''
while 1:
data = s.recv(1024)
logshit(data)
if not data:
break
map_data += data
# got the last chunk of the map
if end_regex.search(map_data):
gomap(map_data) # run the solver
map_data = ''
# We wanted to see if it spawned a shell, it did not.
s.sendall('ls')
data = s.recv(1024)
print 'data: ', data, 'n'
logshit(data)
print 'Connection closed.n'
s.close()
Credits: Antony Stabile, Ditmar Wendt, Luis Sosa, Luis Santana