Coding Challenge 4

This weeks challenge is to write a so called "Pattern Chaser".

Instructions

Language

JavaScript

Expose a function called bnt.patternChaser(str) to the global namespace which takes one string as a parameter and returns "yes [found pattern]" or "no null".

The found pattern should be the longest pattern which can be found in the string.

A pattern for this challenge will be defined as:

• If at least 2 or more adjacent characters within the string repeat at least twice. So for example "aabecaa" contains the pattern "aa", on the other hand "abbbaac" doesn't contain any pattern.
• If str were "aabejiabkfabed" the output should be "yes abe".
• If str were "123224" the output should return "no null".
• The string may either contain all characters (a through z only), integers, or both. But the parameter will always be a string type.
• The maximum length for the string being passed in will be 20 characters.
• If a string for example is "aa2bbbaacbbb" the pattern is "bbb" and not "aa". You must always return the longest pattern possible.

Judging Criteria

• Coding Style:

  • Does the code lint in JSLint with following settings: /*jslint browser: true, plusplus: true, sloppy: true, stupid: false, indent: 4 */
  • Use of language features

• Execution Time

• Lines of code

• Elegance of solution

BONUS!!

Use the Google Closure Library.

If you choose to use the library please create the module in the goog.provide('bnt.PatternChaser'); namespace and make sure it still exposes the bnt.patternChaser(str) function.

Deadline

19:00 - Tuesday 28th May