Dear monks,

I have a little problem here. I also have a solution, but maybe someone has a better one. So the problem is as follows: I have a list of words like : 

mamy
dady
bal
foo
bar
ymamaa
...

[download]
and i need to find out if there is a word which reverse can be matched to any other word in my set. Example: 

    (reverse)   (match)
mamy   -> ymam    ->    ymamaa

[download]
The easiest solution here would be to create a reverse of every word, join them to the original set, label them , sort them (lex. of course). That way 'ymam' and 'ymamaa' would be one next to another and since I have labelled them I can say in O(c) (c=constant) time if there exists a match to the reverse of 'mamy' or not.

Does anyone have a better solution to this ??

Thank you,

Baxy

Update: Thnx chordoba that is true, but i missed out one simple detail. These sets are huge. Therefore regex-ing would take much longer then my sorting suggestion. But yes you are correct (++) Thnx

Update : Yes only from the start ! :) That is also a good solution , but trie's are a bit memory heavy wouldn't you say. so that is why I thought sorting is the simplest one plus building a trie takes in practice much longer then sorting. Wouldn't you say?

In reply to searching problem by baxy77bax

Title:
Use:  <p> text here (a paragraph) </p>
and:  <code> code here </code>
to format your post, it's "PerlMonks-approved HTML":


  • Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!
  • Titles consisting of a single word are discouraged, and in most cases are disallowed outright.
  • Read Where should I post X? if you're not absolutely sure you're posting in the right place.
  • Please read these before you post! —
  • Posts may use any of the Perl Monks Approved HTML tags:
    a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, details, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, summary, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr
  • You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)
            For:     Use:
    & &amp;
    < &lt;
    > &gt;
    [ &#91;
    ] &#93;
  • Link using PerlMonks shortcuts! What shortcuts can I use for linking?
  • See Writeup Formatting Tips and other pages linked from there for more info.