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  1. require 'minitest/autorun'
  2.  
  3. class MovableChar
  4.   def initialize value
  5.     @value = value
  6.     is_letter = @value =~ /[[:alpha:]]/
  7.  
  8.     @move_steps = is_letter ? @value.upcase.ord - 64 : 0
  9.   end
  10.  
  11.   attr_accessor :move_steps, :value
  12.  
  13.   def mark_moved
  14.     @move_steps = 0
  15.   end
  16. end
  17.  
  18. def move(input)
  19.   chars = input.chars.map { |c| MovableChar.new(c) }
  20.  
  21.   while index_to_move = chars.find_index { |c| c.move_steps > 0 }
  22.     char_to_move = chars.delete_at index_to_move
  23.     new_index = (index_to_move + char_to_move.move_steps) % (chars.size + 1)
  24.     char_to_move.mark_moved
  25.     chars.insert(new_index, char_to_move)
  26.   end
  27.  
  28.   chars.map(&:value).join
  29. end
  30.  
  31. describe MovableChar do
  32.   it 'computes moving steps for letters case insensitive' do
  33.     assert_equal 1, MovableChar.new('a').move_steps
  34.     assert_equal 1, MovableChar.new('A').move_steps
  35.     assert_equal 4, MovableChar.new('d').move_steps
  36.     assert_equal 4, MovableChar.new('D').move_steps
  37.   end
  38.  
  39.   it 'moving steps is zero for non-letters' do
  40.     assert_equal 0, MovableChar.new('*').move_steps
  41.     assert_equal 0, MovableChar.new('.').move_steps
  42.     assert_equal 0, MovableChar.new('-').move_steps
  43.     assert_equal 0, MovableChar.new('~').move_steps
  44.   end
  45.  
  46.   it 'is not allowed to move more than once' do
  47.     c = MovableChar.new('a')
  48.     c.mark_moved
  49.     assert_equal 0, c.move_steps
  50.   end
  51. end
  52.  
  53. describe :MovingLetters do
  54.   def test_case_1
  55.     assert_equal 'tca', move('cat')
  56.   end
  57.  
  58.   def test_case_2
  59.     assert_equal '.F.NU', move('F.U.N')
  60.   end
  61.  
  62.   def test_case_3
  63.     assert_equal 'goD', move('Dog')
  64.   end
  65.  
  66.   def test_case_4
  67.     assert_equal '*hibey', move('hi*bye')
  68.   end
  69. end
  70.  
Success #stdin #stdout 0.08s 10688KB
comments (?)
stdin 
Standard input is empty
stdout 
Run options: --seed 45570

# Running tests:

.......

Finished tests in 0.001743s, 4016.6311 tests/s, 7459.4578 assertions/s.

7 tests, 13 assertions, 0 failures, 0 errors, 0 skips
https://ideone.com/gTNvWY
language:
Ruby (ruby 2.5.5)
created:
9 years ago
visibility:
secret

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