Cheap Gas Calculator

cheap_gas_calculator_kata.txt

= Cheap Gas Calculator =
_Is it cheaper to drive across town for cheaper gas prices?_

== Givens / Assumptions ==

* Given: a particular car with its 
 ** hwy MPG, 
 ** tank size and 
 ** current amount of fuel in gallons
* Given: a set of available gas stations with their
 ** distances and
 ** prices per gallon
* Assume: the time spent getting gas is not a consideration
* Assume: the driver and all stations are located along the same stretch 
  of straight highway
* Assume: he best solution may involve going to multiple stations
* Assume: road trip!  Problem is solved as soon as the tank is full

Objective: write a calculator which returns a list of gas stations with 
quantity purchased at each, for cheapest gas.


You could, *for instance*, setup something like this:
{ "Shecelle C. Shell" => [2, 0.00],
   "Fissile Phillips Filling Station" => [7, 10.00],
   "E Friendly St. BP" => [12, 10.00],
   "Olig's OPEC and Overpriced Emporium" => [23, 10.00] }

then pass this:
{ :mpg => 2,
  :tank_size => 25,
  :in_tank => 10 }

And get this:

[ 
 ["Shecelle C. Shell", 16]
]

== Problem Data ==

You have a monster truck with a 25 gallon tank which gets 2 mpg

Here are some stations and their distances:
    | Name                                | Distance |
    | Shecelle C. Shell                   | 2 miles  |
    | Fissile Phillips Filling Station    | 7 miles  |
    | E Friendly St. BP                   | 12 miles |
    | Olig's OPEC and Overpriced Emporium | 23 miles |

== Some possible starting scenarios:

given you've got 2 gallons in the tank
and the shell station has free gas

given you've got a hypercar which gets 1 mpg
given 23 gallons in the tank
and Olig's has free gas
and everybody else is charging $100/gallon









New Requirement! (for extra credit):
* Rental Agency: after getting gas, drive always returns to point of origin