[2017][ruby][3.x] refactor spiral enumerator

sorbet
Alpha Chen 7 years ago
parent be421a9943
commit 9ff29145e6

@ -2,61 +2,35 @@ require "minitest"
class Spiral
def initialize
@square = [0,0]
@dir = [1,0]
@steps = [1, 1]
@state = [0,0]
end
def each
return enum_for(__method__) unless block_given?
loop do
yield @square
step!
end
end
private
(1..Float::INFINITY).lazy
.flat_map {|i| [i, i] }
.zip(%i[r u l d].cycle)
.flat_map {|n,d| Array.new(n, d) }
.each do |dir|
def step!
@steps[0] -= 1
@square = @square.zip(@dir).map {|i,j| i+j }
if @steps[0] == 0
change_dir!
@steps << next_steps
@steps.shift
end
yield @state
@state = @state.zip(
case dir
when :r
[1, 0]
when :u
[0, 1]
when :l
[-1, 0]
when :d
[0, -1]
end
).map {|a,b| a + b }
def change_dir!
@dir = case @dir
when [1,0]
[0,1]
when [0,1]
[-1,0]
when [-1,0]
[0,-1]
when [0,-1]
[1,0]
else
raise "invalid dir: #@dir"
end
end
def next_steps
case @dir
when [1,0]
@steps[1]
when [0,1]
@steps[1] + 1
when [-1,0]
@steps[1]
when [0,-1]
@steps[1] + 1
else
raise "invalid dir: #@dir"
end
end
end
class Grid

Loading…
Cancel
Save