amarduwal / assignment

Solution for number to possible words or combinations of words from the provided dictionary, that can be mapped back as a whole to the number.

Number to possible words conversion

Given a 10 digit phone number, you should return all possible words or combinations of words from the provided dictionary, that can be mapped back as a whole to the number. With this we can generate numbers like 1-800-motortruck which is easier to remember than 1-800-6686787825.

The phone number mapping to letters is as follows:

2 = a b c
3 = d e f
4 = g h i
5 = j k l
6 = m n o
7 = p q r s
8 = t u v
9 = w x y z

The phone numbers will never contain a 0 or 1. Words have to be at least 3 characters.

To give you an initial idea, here are some numbers that return (a lot of) results. 6686787825 returns a (long) list with at least these word combinations:

• motortruck
• motor, truck
• motor, usual
• noun, struck
• not, opt, puck

2282668687 returns a (long) list with at least these word combinations:

• catamounts
• acta, mounts
• act, amounts
• act, contour
• cat, boot, our

The conversion of a 10 digit phone number should be performed within 1000ms.

Execution

Copy and paste this line to the Terminal and press Enter.

git clone https://github.com/amarduwal/assignment.git

Browse to root folder

cd assignment

Run code as below

ruby number_conversion.rb

OR

time ruby number_conversion.rb

Instruction

Successfully execute code on ruby 2.6.2. It requires 'pry'(for debugging) gem and 'benchmark'(to measure performance) for execution. And 'Rspec' for testing. So if your system doesn't have those gem please install before execution.

• To install pry

gem install pry

• To install RSpec

gem install rspec