Simple Maths algorithm

I require a simple Maths algorithm which is broken down into steps that a simple C or Java application can implement; Simpler the algorithm the better. Problem: 1. 90% of the time a string of 11 characters long of type 0...9 which always starts with "0" Example String "01234567891" 2. 10% of the time a string length of 12..14 characters long Objective Compress the String of characters to a reduced amount of characters. Rules We can support characters of 0...9 and characters A,B,C,D Provide Please provide a pseudo algorithm which demonstrates compressing the string and un-compressing the string. ## Deliverables 1) Complete and fully-functional working program(s) in executable form as well as complete source code of all work done. 2) Deliverables must be in ready-to-run condition, as follows? (depending on the nature? of the deliverables): a)? For web sites or? other server-side deliverables intended to only ever exist in one place in the Buyer's environment--Deliverables must be installed by the Seller in ready-to-run condition in the Buyer's environment. b) For all others including desktop software or software the buyer intends to distribute: A software? installation package that will install the software in ready-to-run condition on the platform(s) specified in this bid request. 3) All deliverables will be considered "work made for hire" under U.S. Copyright law. Buyer will receive exclusive and complete copyrights to all work purchased. (No GPL, GNU, 3rd party components, etc. unless all copyright ramifications are explained AND AGREED TO by the buyer on the site per the coder's Seller Legal Agreement). * * *This broadcast message was sent to all bidders on Sunday Nov 23, 2008 8:40:23 AM: I'm sorry - The specification should have stated Allowed characters in the compressed String are (supported 0...9 A, B, C, and D) The purpose of the application is phone - telephony - transmitting DTMF tones ## Platform NA