# coding: utf-8
require 'minitest/autorun'
 
F=->s{d=[1,w=1e4,-1,-w]
v=[w]+s.chars.map{|c|w+=d.rotate!(c<?R?-1:c>?R?0:1)[0]}
v==v&v}
 
describe '#F' do
  describe 'valid slithers' do
    def test_first_case
      assert F['SRSLSSLRLRSSRSRSS']
    end
 
    def test_valid
      assert F['SSLSLSRSRSSRSSSLLSSSRRLRSLRLLSSS']
    end
    def test_a_hilbert_curve
      assert F['SRRLSLLRRLLSLRRSRLLRSRRLLRRSRLLSSLLRSRRLLRRSRLLRSRRLSLLRRLLSLRR']
    end
    def test_another_valid
      assert F['RLLRSRRLSLLRRLLSLRRSRLLRSRRLLRRSRLLSSLLRSRRLLRRSRLLRSRRLSLLRRLLSLRRSRLLRSRRLLRRSRLLSSLLRSRRLLRR']
    end
    def test_Spiral
      assert F['SRRSRSRSSRSSRSSSRSSSRSSSSRSSSSRSSSSSRSSSSSRSSSSSSRSSSSSSRSSSSSS']
    end
    def test_bigger_squigglier_spiral
      assert F['SSSSSSSSSSLSSSSSSSLSSSSSSSSLSSSSSLSSSSSSLSSSLLRRLLRRLLSLSSSRRSSSSRSSSRSSSSSSRSSSSSRSSSSSSSSRSSSSSSSRSSSSSSSSS']
    end
    def test_yet_another_valid
      assert F['LRSLLRLSRSLLSRLSLRSLSSSLRRSSLSRRLRSRLRLSLRLLRLRSSLSLRLRSRSSSSSLSRRLSLSSSRRLRLRLRLRRLLSSLSSSRRLRLRLRLRLSLSSSSSSSSSSSSSRLRLLRLRLRLRLRLRLRLSLSSSLSLSLL']
    end
  end
 
  describe 'invalid slithers' do
    def test_invalid_1
      refute F['SRRLSLLRRLLSLRRSRLLRSRRLLRRSRLLLLRSRRLLRRSRLLRSRRLSLLRRLLSLRR']
    end
    def test_invalid_2
      refute F['SRRLSLLRRLLSLRRSRLLRSRRLLSRSSSRSSSSSSSRSRSSSSSSSRRLLRRSRLLRSRRLSLLRRLLSLRR']
    end
    def test_invalid_3
      refute F['SRRSRSRSSRSSRSSSRSSSRSSSSSSSSSSRSSSSRSSSSSRSSSSSRSSSSSSRSSSSSSRSSSSSS']
    end
    def test_invalid_4
      refute F['SSSSSSSSSSLSSSSSSSLSSSSSSSSLSSSSSLSSSSSSLSSSLLRRLRLRRLLSLSSSRRSSSSRSSSRSSSSSSRSSSSSRSSSSSSSSRSSSSSSSRSSSSSSSSS']
    end
    def test_invalid_5
      refute F['LRSLLRLSRSLLSRLSLRSLSSSLRRSSLSRRLRSRLRLSLRLLRLRSSLSLRLRSRSSSSSLSRRLSLSSSRRLRLRLRLRRLLSSLSSSRRLRLRLRLRLSLSSSSSSSSSSSSSRLRLLRLRLRLRLRLRLRLSLSSSLSLSLLSLRLSLRSLRSLRSLSLSLRSRLSLRSLRLSRSLLLRLRLRRRRSLSLSSLLSLSLSLSSLLSLSLLRLRSLLRSRLSLSSLLLLSSSSSSSSSSSSSSSSSSSSRLRLLRRLRLRLLRLRLRLRLRLSSSSLSLRLLRLSLSSLSLSLSLSLRLLRLSLLLSRSSSSSSSSSSSSSSSRLRLRLLRLRLSLSRSRSSSLSRLRLRLRSLSLSLSRLLSRLSLSLSLSLSSLSLSLLSLSRLLRLRLRLRLRLRLRLRLRLRLSLSRLRLSLLRRLSLLSLSLSLSLSLLSLSLSLRLRLRLRLRLRLRLRLRLRRLRSLSLSLSLSLSLSLSSLSSSSSLSLSSSLSLSLSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSS']
    end
  end
end
 
 
 

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