Win a copy of TensorFlow 2.0 in Action this week in the Artificial Intelligence and Machine Learning forum!
  • Post Reply Bookmark Topic Watch Topic
  • New Topic
programming forums Java Mobile Certification Databases Caching Books Engineering Micro Controllers OS Languages Paradigms IDEs Build Tools Frameworks Application Servers Open Source This Site Careers Other all forums
this forum made possible by our volunteer staff, including ...
  • Campbell Ritchie
  • Liutauras Vilda
  • Paul Clapham
  • Bear Bibeault
  • Jeanne Boyarsky
  • Ron McLeod
  • Tim Cooke
  • Devaka Cooray
Saloon Keepers:
  • Tim Moores
  • Tim Holloway
  • Jj Roberts
  • Stephan van Hulst
  • Carey Brown
  • salvin francis
  • Scott Selikoff
  • fred rosenberger

A fun algorithm for All possible combinations of alphabets

Ranch Hand
Posts: 207
jQuery Eclipse IDE Firefox Browser
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator

yesterday I saw this Post about All possible combinations of alphabets.

Problem was to generate all combination of 3 and 4 characters input e.g. abc or abcd.

I know this problem is not very difficult and can be solved without much brain storming but I have come up with a rather different algorithm for this.

If you see "aaaa" or "aaa" first thought comes up that they are Strings but if you think in terms of "base 36" number system these normal strings can be converted into integers.

So if you want every combination of "aaaa" to "zzzz" then you just have to iterate from integer aaaa to zzzz.

so in base 36:
aaaa+1 == aaab similarly upto aaaz
but after aaaz you have to add 11
aaaz+11 == aaba

similarly if you take care of appropriate increments then you can generate all strings in one go:

this is the code for printing all combinations for 4 letter strings:

I also wrote a general recursive function using same approach for generating all combinations of Strings of any number of characters.

I am not saying that this algo is very efficient, and of course this algo will be of limited use because of the limitations of int size. but its just a different and fun approach.
What do you think?
lowercase baba
Posts: 12916
Chrome Java Linux
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator
I've done something like this when trying to count how many times you need each 'digit' to write the numbers 1 - 999999. I realized that it is very similar to a car's odometer, and proceeded from there.

Of course, the downside is that it doesn't find the string "ab" for the input "abcd", but that may not be part of your requirements.
    Bookmark Topic Watch Topic
  • New Topic