Similar to this question, but this is a crossword variation!

Instead of only one letter per grid square, you can have one or two.


  • A 2d array, or whatever works in your language.
  • You can assume valid inputs
  • Any array size must work


  • An array of all the words
    • Across and down
    • All words must be joined together, i.e. linked in an unbroken chain of words (if not return false)
    • Words must be at least two grid squares, not letters


[["",  "wo", "r",  "k"],
[ "",   "r",  "",   ""],
[ "he", "l",  "lo", ""],
[ "",   "d",  "ad", ""]]


["work", "world", "hello", "load", "dad"]


[["he", "ll", "o"],
[ "",   "",   ""],
[ "wo", "r",  "ld"]]



This is , so I'll be running this on windows 7 with 2.5ghz and 16gb of ram. If your code is really esoteric, provide a link to the compiler so I can actually run it.

  • 9
    \$\begingroup\$ Welcome to PPCG! \$\endgroup\$
    – FlipTack
    Commented Dec 18, 2016 at 18:10
  • 2
    \$\begingroup\$ You should replace the two spaces part with two grid squares. \$\endgroup\$ Commented Dec 19, 2016 at 14:04
  • 1
    \$\begingroup\$ What size input size will the speed be measured with? \$\endgroup\$ Commented Dec 19, 2016 at 14:06
  • \$\begingroup\$ @MartinEnder the examples \$\endgroup\$
    – epicbob57
    Commented Dec 19, 2016 at 19:14
  • \$\begingroup\$ @epicbob57 That seems way to small to measure reliable timings. You'd mostly be measuring I/O and other overhead. \$\endgroup\$ Commented Dec 19, 2016 at 19:15

1 Answer 1


Python 3

import numpy
from scipy.ndimage import measurements

def crosswords(arr):
    # check connectivity
    if measurements.label(numpy.where(M!='',1,0))[-1] != 1:
        return 'false'

    words = []
    def get_words(mat):
        for r in mat:
            for c in r:
                if c=='':
                    if counter>1:
                    word, counter = '', 0
                    word, counter = word+c, counter+1
            if counter > 1:
    # transpose M
    return words


Function takes an array of array of strings as input:

crosswords( [["", "wo", "r", "k"], [ "", "r", "", ""], [ "he", "l", "lo", ""], [ "", "d", "ad", ""]])

Returns the string false when connectivity returns multiple labels. Returns array of valid words otherwise.

I timed it with timeit, time.time() and using the console command time and but I don't know which one to use or which one to post here.

  • \$\begingroup\$ I realized that I don't have Python 3... anyway, I'll be testing it using time.time() \$\endgroup\$
    – epicbob57
    Commented Dec 19, 2016 at 19:18
  • \$\begingroup\$ I can't seem to install scipy using pip... \$\endgroup\$
    – epicbob57
    Commented Dec 20, 2016 at 0:16
  • \$\begingroup\$ did you use pip3 ? \$\endgroup\$ Commented Dec 20, 2016 at 0:16
  • \$\begingroup\$ pip 9.0.1 (python 3.5) \$\endgroup\$
    – epicbob57
    Commented Dec 20, 2016 at 0:19
  • \$\begingroup\$ oh you are on windows, try it with admin priviliges \$\endgroup\$ Commented Dec 20, 2016 at 0:28

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.