Technical test for interviewing Ruby developer
Graphical editors allow users to edit images in the same way text editors let us modify documents.
Images are represented as an M x N array of pixels with each pixel given colour.
Produce a program that simulates a simple interactive graphical editor.
The input consists of a line containing a sequence of commands. Each command is represented by a single capital letter
at the start of the line. Arguments to the command are separated by spaces and follow the command character.
Pixel co-ordinates are represented by a pair of integers: 1) a column number between 1 and M, and 2) a row number
between 1 and N. Where 1 <= M, N <= 250. The origin sits in the upper-left of the table.Colours are specified by capital letters.
The editor supports 7 commands:
- I M N – Create a new M x N image with all pixels coloured white (O).
- C – Clears the table, setting all pixels to white (O).
- L X Y C – Colours the pixel (X,Y) with colour C.
- V X Y1 Y2 C – Draw a vertical segment of colour C in column X between rows Y1 and Y2 (inclusive).
- H X1 X2 Y C – Draw a horizontal segment of colour C in row Y between columns X1 and X2 (inclusive).
- F X Y C – Fill the region R with the colour C. R is defined as: Pixel (X,Y) belongs to R. Any other pixel which is the same colour as (X,Y) and shares a common side with any pixel in R also belongs to this region.
- S – Show the contents of the current image
- X – Terminate the session
In the example below, > denotes input, => denotes program output.
> I 5 6 > L 2 3 A > S OOOOO OOOOO OAOOO OOOOO OOOOO OOOOO > F 3 3 J > V 2 3 4 W > H 3 4 2 Z > S JJJJJ JJZZJ JWJJJ JWJJJ JJJJJ JJJJJ
We prefer submissions in Ruby although if this is a problem please contact us. It is not compulsory to
submit a fully completed answer within the time allowed.
Please provide an executable solution with any source files in a common archive format (ZIP, RAR, TAR
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