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A typing speed test loads up a dictionary of words, and gives you one to type: pinball. You, with your fast but inaccurate fingers, type in pinbnal. Darn it!

Make a program that will print out a random word from a dictionary, then ask for the user to type this word back, and finally return whether or not they got the word right. The catch is: the program must accept minor typos.

Accept a typo if it has only one of the following:

  • one letter is repeated in the input 1 or 2 more times. Only accept the letter if it is directly adjacent to a letter it is next to.
  • one letter in the word is repeated 1 time.
  • 2-4 of the letters in the input are scrambled.

Some acceptable typos of the word pinball are:
pingball pinbala pinbanll
Some unacceptable typos:
pibnannl maxwell pinbalgl

Shortest code wins. Good luck.

share|improve this question
an ingteresring undereretanding ohf what a minoe typpe is... what exactly does "scrambled" include, apparently it's not just swapping letters? – ceased to turn counterclockwis Jul 4 '12 at 6:57
e.x. water -> waert (ert is scrambled ter) or wtrae (trae is scrambled ater) – beary605 Jul 4 '12 at 7:02
But what's pinbala or pinbnal then? The second l is missing completely in both cases. – ceased to turn counterclockwis Jul 4 '12 at 7:35
And pingball adds a new letter - it's fundamentally the same error as pinbalgl. – Peter Taylor Jul 4 '12 at 8:07
I've fixed the parameters to fit my examples. – beary605 Jul 4 '12 at 15:10

1 Answer 1

Mathematica 179

Edit: As Primo correctly notes, the following does not adhere to the constraint of pardoning only those intrusions from QWERTY neighbors. DL distance, of course, has nothing to do with distance on a keyboard. Oh, well. I'll leave up my response, which someone with more patience will easily better.


d = DictionaryLookup[]; i = d[[RandomInteger@{1, Length@d}]];o = InputString["Type: " <> i];
Print["in: ", i, "\nout: ", o, "\n", Switch[i~DamerauLevenshteinDistance~o, 0, "perfect",
1, "ok", _, "wrong"]]


  1. d = DictionaryLookup[] stores a built-in dictionary of 92 k English words in d.
  2. i = d[[RandomInteger@{1, Length@d}]] selects a random word and stores it in i.
  3. o = InputString["Type: " <> i]; opens a dialog window (see figure) with the prompt "Type [i]."
  4. i~DamerauLevenshteinDistance~o computes the Damerau-Levenshtein distance beween the requested word and the word typed by the user. If the DL distance = 0, "perfect"; if the DL distance = 1, "ok"; otherwise, "wrong".


Test Results

For the first 7 tests, the input string, i, was manually set to "pinball". The results were as desired with the exception of "pinbalgl", which was considered acceptable because it returns a DL distance value of 1.

in: pinball
out: pinball

in: pinball
out: pingball

in: pinball
out: pinbala

in: pinball
out: pinbanll

in: pinball
out: pinbannl

in: pinball
out: maxwell

in: pinball
out: pinbalgl

in: tureen
out: turen

in: feeder
out: feedr

in: tarmacs
out: tarmax

share|improve this answer
I like the interface :D Not sure if it answers the question exactly as stated though. Judging from the examples, (I think) it should accept an inserted character (and here's where the wording gets a bit unclear) if and only if one or both of the two characters it is adjacent to in the string is also adjacent to it on a keyboard (presumably qwerty). A test slightly stronger than the Levenshtein distance. – primo Dec 17 '12 at 19:06
@primo. I see your point. I missed entirely the constraint about adjacent keys. Clearly, that would require considerably more coding. – David Carraher Dec 17 '12 at 19:12
Even so, I would still consider this an acceptable solution, given the lack of participation. You already have my +1 – primo Dec 17 '12 at 19:33
Thanks. I thought the question looked lonely and abandoned being unanswered. So I gave it my best shot. To craft a fully suitable response, I'd need more time than I have. – David Carraher Dec 17 '12 at 19:46

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