One obvious problem is the use of string instead of symbols. It was a bad bad mistake. So big if I had been the person testing, I would have thought very bad of myself.
Anyway it was clear that Java version was considerably more verbose.
So one obvious improvement is using symbols instead of string. But during the interview, I asked what other improvements people have done on the assignment. One tip I received is the use of Array.rotate. I don't like that improvement, because it makes the code less understandable. But I didn't like the verbosity of the case, and I tested a different approach. This is the code I left in the end:
class Robot
VALID_X = 0..4
VALID_Y = 0..4
VALID_F = [:NORTH,:SOUTH,:EAST,:WEST]
TURN_RIGHT = {:SOUTH=>:WEST,:NORTH=>:EAST,:EAST=>:SOUTH,:WEST=>:NORTH}
TURN_LEFT = {:SOUTH=>:EAST,:NORTH=>:WEST,:EAST=>:NORTH,:WEST=>:SOUTH}
MOVE = {:SOUTH=>[0,-1],:NORTH=>[0,1],:EAST=>[1,0],:WEST=>[-1,0]}
def initialize
@accepting=false
end
def place(cols,rows,facing)
x=cols.to_i
y=rows.to_i
f=facing.to_sym
if is_valid?(x,y,f)
@x=x
@y=y
@f=f
@accepting=true
end
end
def left
return unless @accepting
@f=TURN_LEFT[@f]
end
def right
return unless @accepting
@f=TURN_RIGHT[@f]
end
def move
return unless @accepting
delta=MOVE[@f]
x = @x + delta[0]
y = @y + delta[1]
if is_valid?(x,y)
@x=x
@y=y
end
end
def report
return nil unless @accepting
"#{@x.to_s},#{@y.to_s},#{@f}"
end
protected
def is_valid?(x,y,f=@f)
VALID_X.include?(x) && VALID_Y.include?(y) && VALID_F.include?(f)
end
end
