How to send a mobile phone "business card"?

I always get confused about how to send a person's data saved in my mobile phone address book to another person who is also in my address book. For example, say my friend "seeker" wants to know the contact information about another friend "sought". On my phone which is an antiquated (pre-2003) model of Nokia (I cannot say which one it is since there is nothing on the instrument that tells me what model it is) I can follow the following steps:

- look up information about "sought"
- choose "options" and then choose "send bus. card"
- choose (say) "via text msg."
- look up information about "seeker"
- choose to "send the business card"

I always get confused which order to do my search in (do I lookup "sought" and send his info. to "seeker" or do I look up "seeker" and send him information about "sought"?) and I thought others too may have that confusion hence thought I should record this permanently.

- Rajendra Gokhale

Words containing letters in alphabetical order

My daughter Rama asked me this question the other day - which is the longest word that contains all letters in alphabetical order? For a dyed-in-the-wool UNIX hacker like me, the answer was quite straightforward:

grep -i "a*b*c*d*e*f*g*h*i*j*k*l*m*n*o*p*q*r*s*t*u*v*w*x*y*z*" /usr/share/dict/words

Interestingly enough, I had left out the "*" at the end of the regular expression so all the words I found were ones ending in "z". That taught me a new word - "chintz" which interestingly enough originates from Hindi and is a type of cotton fabric. My daughter alerted me to my bug when she pointed out that the word "fix" did not appear in my output. I was able to correct my error and rerun the program. One of the longest words fulfilling the requirements of the problem was "biopsy".

Many of my posts may seem like nice ways to kill time but these skills really come handy in ones day-to-day work - for example, in my role as manager I was able to put my skills to good use in order to figure out the productivity of my (Research) group. But that will be another posting for some other day.

- Rajendra Gokhale

Solving the hexagon problem using Perl

Here is a problem that I see quite often in one of the afternoon papers such as the "MidDay". You are shown a hexagon, all of whose sides are labelled with one English letter (see above). There is another letter at the centre of the hexagon. The challenge is to make as many words of four or more letters from the letters of the hexagon.

In making a word, each letter must be used once only. Each word must contain the central letter. There should be atleast one seven letter word. Plurals, foreign words & proper names are not allowed.

Given such a hexagon (encoded in some format of your choice) and a file consisting of all acceptable words (e.g. /usr/share/dict/words), can you write a program to solve this problem?

See the Perl program below that does this job quite elegantly. A small point - when I used the dictionary on my Redhat Linux (Fedora Core 3), I could not find the seven letter word because it was missing from the dictionary - I had to figure it out manually. The word was "website" and we are talking of the year 2006 A.D. :-)!

Here is the Perl program:

use strict;
my $regex = '^b{0,1}e{0,2}i{0,1}s{0,1}tw{0,1}$';

foreach my $word (<>)
{
chop $word;
my $newword = join "", (sort (split //, $word));
if ($newword =~ /$regex/ && length($word) >= 4){
print "${word}\n";
}
}
__END__
As you can see above, the regular expression from the image shown was hardcoded into the script but anyone who understands this program will be able to trivially modify it so that the regular expression can be constructed on the fly. Also one small optimization that is possible involves precompiling the regular expression.

- Rajendra Gokhale