samverrall/rover-test

Mars Rover Challenge

Running the project

main.go contains a hardcoded string input which directly calls the parser.Parse() function, returning the vehicles + grid size.

This progam could be extended using the Go standard lib flag package to accept instructions into the program. As we have a vehicle interface the program could also be extended to support more vehicle types. Currently only the vehicle/rover package satisfies the vehicle interface.

To see the result of the hardcoded input please run:

$ go run main.go

Running tests

$ ./testandlint.sh

Running testandlint.sh requires the golangci-lint Go linter installed on your machine.

Install golangci-lint

• Installation
• Github

Packages

• cooordinates Handles coordinate movements on vehicles, and supplies an interface + mock implementation.
• direction Handles rotating the vehicle by tracking its current direction and deciding its Left() and Right() movements, for example if the current direction is North we know that the Right() function and Left() function calls would return West and East. Likewise if it was South it's Left() and Right() would return East and West.
• parser Handles string input for vehicle instructions, plateau size and vaidates the input. Incorrect inputs will return an error, valid input will be executed using the vehicle nagivation function.
• vehicle defines an interface with the required implementation for a vehicle. vehicle/rover satisfies this interface.
• plateau Initialises a new mars rover grid with the supplied grid width and grid height from the string instructions.

Improvements / Refactoring that I'd Implement

• Review the data structure of the parsed instructions.

Example input

5 5

1 2 N

LMLMLMLMM

3 3 E

MMRMMRMRRM

Expected output of example

1 3 N

5 1 E

About the challenge

A squad of robotic rovers are to be landed by NASA on a plateau on Mars. This plateau, which is curiously rectangular, must be navigated by the rovers so that their on board cameras can get a complete view of the surrounding terrain to send back to Earth. A rover's position is represented by a combination of an x and y co-ordinates and a letter representing one of the four cardinal compass points. The plateau is divided up into a grid to simplify navigation. An example position might be 0, 0, N, which means the rover is in the bottom left corner and facing North. In order to control a rover, NASA sends a simple string of letters. The possible letters are 'L', 'R' and 'M'. 'L' and 'R' makes the rover spin 90 degrees left or right respectively, without moving from its current spot. 'M' means move forward one grid point, and maintain the same heading. Assume that the square directly North from (x, y) is (x, y+1).