Robots

https://github.com/neilkennedy/coding-challenge-martian-robots/blob/master/readme.md

Deliverables

Improvements

These are sub-tasks which could improve the application, but was unable to complete due to time constraints.

1. [4] Determine rotations in RobotHeading by tracking a numeric value corresponding to the RobotHeading or use a Doublely Linked List. I started with this approach, but it seemed overengineered for a first pass
2. [2] Better abstraction of RobotsCollection.AddRobots logic
3. [2] Build user interface

Assumptions

1. I assumed 03 W is bad data and corrected this to 0 3 W for automated tests. There should be a space in order to parse properly. "Smarter parsing" could be an improvement task if this is good data, allowing for optional parameters (ie x = 3, y = some default value, bearing = W) I am still having difficulty getting this working after enhancing parsing logic assuming the first numeric value is X.
2. The maximum value for any coordinate is 50. The design I implemented does not have a ceiling for compatible coordinate values, therefore I do not believe a handle (error or warning) is necessary for this condition.
3. All instruction strings will be less than 100 characters in length. The design I implemented does not have a ceiling for number of compatible instruction characters, therefore I do not believe a handle (error or warning) is necessary for this condition.
4. Assuming all bounded parameters are inclusive (ie if a Robot is on 0,0 they are not outside the grid)

Architecture

I used an MVC approach to designing this application. All parsing and business logic is performed in the Controller namespace. Assumptions were minimized due to heavy use of Configuration settings.

Deliverable Time

So far about 4 hours of time have been spent completing this project. A good architecture is in place to complete remaining tasks, which I have estimated at 8 additional hours of work. See Improvements list for suggestions and time estimates.

Programming Problem

Introduction

Design & implement a solution using C#/ASP.Net MVC or ASP.Net core to solve the problem described below. The objective of the problem is to allow the candidate to demonstrate their design principles and development skills. The problem is provided with sample data to be used for testing and the candidate should be able to demonstrate their solution using the supplied data in the form of a unit test or a simple user interface.

Expected Outcome

On completion of this task, we expect to receive:

• An architecture & design overview describing your application design of the entire solution. Specifically we are interested in seeing:
• List of assumptions that you made
• An estimate of how long this would take if you were asked to build the entire solution for a customer
• Source code (including any automated tests)

Problem: Martian Robots

The Problem

The surface of Mars can be modelled by a rectangular grid around which robots are able to move according to instructions provided from Earth. You are to write a program that determines each sequence of robot positions and reports the final position of the robot. A robot position consists of a grid coordinate (a pair of integers: x-coordinate followed by ycoordinate) and an orientation (N, S, E, W for north, south, east, and west). A robot instruction is a string of the letters “L”, “R”, and “F” which represent, respectively, the instructions:

• Left : the robot turns left 90 degrees and remains on the current grid point.
• Right : the robot turns right 90 degrees and remains on the current grid point.
• Forward : the robot moves forward one grid point in the direction of the current orientation and maintains the same orientation. The direction North corresponds to the direction from grid point (x, y) to grid point (x,y+1). There is also a possibility that additional command types maybe required in the future and provision should be made for this.

Since the grid is rectangular and bounded, a robot that moves “off” an edge of the grid is lost forever. However, lost robots leave a robot “scent” that prohibits future robots from dropping off the world at the same grid point. The scent is left at the last grid position the robot occupied before disappearing over the edge. An instruction to move “off” the world from a grid point from which a robot has been previously lost is simply ignored by the current robot.

Input

The first line of input is the upper-right coordinates of the rectangular world, the lower-left coordinates are assumed to be 0,0. The remaining input consists of a sequence of robot positions and instructions (two lines per robot). A position consists of two integers specifying the initial coordinates of the robot and an orientation (N, S, E, W), all separated by white space on one line. A robot instruction is a string of the letters “L”, “R”, and “F” on one line. Each robot is processed sequentially, i.e., finishes executing the robot instructions before the next robot begins execution. The maximum value for any coordinate is 50. All instruction strings will be less than 100 characters in length.

Output

For each robot position/instruction in the input, the output should indicate the final grid position and orientation of the robot. If a robot falls off the edge of the grid the word “LOST” should be printed after the position and orientation.

Sample Input

5 3

1 1 E

RFRFRFRF

3 2 N

FRRFLLFFRRFLL

03 W

LLFFFLFLFL

Sample Output

11 E

3 3 N LOST

2 3 S