As for binary searching for first letters in a sorted dictionary, I've done that in my submission to the word ladder problem which was a problem in perl quiz of the week expert edition week 22.

However, I don't quite see how that would help in this word selection problem. Unless you somehow preprocess the dictionary, you cannot select a random word in constant time even if you know the offsets of the first letters, as just choosing a random offset favors long words. So, IMO, you have to read the whole or most of the dictionary file for this problem unless it's preprocessed in some way. Random access to the file may still slightly help after reading it completely, but not very much unless there are very long words in the "dictionary".

In reply to Re^2: improving the efficiency of a script by ambrus
in thread improving the efficiency of a script by sulfericacid

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.