Ruby: Oblongular Number Spirals Solution

  1 # Oblongular Number Spirals
  2 # http://codegolf.com/oblongular-number-spirals
  3 
  4 class Spiral
  5   attr_accessor :row_num, :col_num, :direction
  6   
  7   def initialize(m, n)
  8     @spiral = []
  9     @value = 0
 10     @row_num = m
 11     @col_num = n
 12     @direction = :right
 13   end
 14   
 15   def get(row, col)
 16     if (row < 0 || row >= row_num || col < 0 || col >= col_num)
 17         raise RangeError.new("Out of Bound : row = #{row} col = #{col}")
 18     end
 19     @spiral[row] ||= Array.new
 20     @spiral[row][col] ||= nil
 21     @spiral[row][col]
 22   end
 23   
 24   def increment_fill(row, col)
 25     @value += 1
 26     fill(row, col, @value)
 27   end
 28   
 29   def fill(row, col, value)
 30     if (row < 0 || row >= row_num || col < 0 || col >= col_num)
 31       raise RangeError.new("Out of Bound : row = #{row} col = #{col}")
 32     end
 33     @spiral[row] ||= Array.new
 34     @spiral[row][col] = value
 35   end
 36   
 37   def populate(x = 0, y = 0)
 38     count = 0
 39     while (1)
 40       increment_fill(x, y)
 41       count += 1
 42       # exit the loop once iteration == total_cells
 43       break if count == row_num * col_num
 44       x, y = next_cell(x, y) 
 45     end
 46   @spiral
 47   end
 48   
 49   def next_cell(row, col)
 50     new_row = row
 51     new_col = col
 52 
 53     case @direction
 54     when :right
 55       new_col = col + 1
 56     when :left
 57       new_col = col - 1
 58     when :down
 59       new_row = row + 1
 60     when :up
 61       new_row = row - 1
 62     end
 63 
 64     if ((new_col >= col_num || new_col < 0))
 65       change_direction
 66       next_cell(row, col)
 67     elsif ((new_row >= row_num || new_row < 0))
 68       change_direction
 69       next_cell(row, col)
 70     elsif (get(new_row, new_col) != nil)
 71       change_direction
 72       next_cell(row, col)
 73     else
 74       return [new_row, new_col]
 75     end
 76   end
 77   
 78   def change_direction
 79     case @direction
 80     when :right
 81       @direction = :down
 82     when :down
 83       @direction = :left
 84     when :left
 85       @direction = :up
 86     when :up
 87       @direction = :right
 88     else
 89       raise ArgumentError.new("Illegal value  for current_direction #{@direction}")
 90     end
 91   end
 92 
 93   def dump
 94    display = ''
 95    @spiral.each do |row|
 96      row.each do |col|
 97        display << sprintf("%3d ", col)
 98      end
 99      display << "\n"
100    end
101    puts display
102   end
103 end
104 
105 if $0 == __FILE__
106   s = Spiral.new(ARGV[1].to_i, ARGV[0].to_i)
107   s.populate
108   s.dump
109 end
110 

  1 $:.unshift File.join(File.dirname(__FILE__),'..','lib')
  2 
  3 require 'test/unit'
  4 require 'spiral'
  5 
  6 class TestSpiral < Test::Unit::TestCase
  7   def setup
  8     @spiral = Spiral.new(4, 5)
  9   end
 10 
 11   def test_increment_fill_0_0_first
 12     @spiral.increment_fill(0, 0)
 13     assert_equal(1, @spiral.get(0, 0))
 14   end
 15 
 16   def test_increment_fill_1_1_first
 17     @spiral.increment_fill(1, 1)
 18     assert_equal(1, @spiral.get(1, 1))
 19   end
 20 
 21   def test_increment_fill_successive
 22     @spiral.increment_fill(0,0)
 23     @spiral.increment_fill(0,1)
 24     @spiral.increment_fill(1,1)
 25     assert_equal(3, @spiral.get(1, 1))
 26   end
 27 
 28   def test_get_beyond_limit_raises_exception
 29     assert_raise(RangeError) {
 30       @spiral.get(@spiral.row_num + 1, @spiral.col_num + 1)
 31     }
 32   end
 33 
 34   def test_get_below_zero_raises_exception
 35     assert_raise(RangeError) {
 36       @spiral.get(-1, 0)
 37     }
 38   end
 39 
 40   def test_get_at_limit_raises_exception
 41     assert_raise(RangeError) {
 42       @spiral.get(@spiral.row_num, @spiral.col_num)
 43     }
 44   end
 45 
 46 
 47   def test_unfill_get_with_in_range_does_not_raise_exception
 48     assert_nothing_raised() {
 49       @spiral.get(@spiral.row_num - 1, @spiral.col_num - 1)
 50     }
 51   end
 52 
 53   def test_unfill_get_with_in_range_returns_nil
 54     assert_equal(nil, @spiral.get(@spiral.row_num - 1, @spiral.col_num - 1))
 55   end
 56 
 57   def test_fill_beyond_range_raises_exception
 58     assert_raise(RangeError) {
 59       @spiral.increment_fill(@spiral.row_num + 1, @spiral.col_num + 1)
 60     }
 61   end
 62 
 63   def test_fill_beyond_range_raises_exception
 64     assert_raise(RangeError) {
 65       @spiral.increment_fill(0, -1)
 66     }
 67   end
 68 
 69   def test_fill_at_range_raises_exception
 70     assert_raise(RangeError) {
 71       @spiral.increment_fill(@spiral.row_num, @spiral.col_num)
 72     }
 73   end
 74 
 75   def test_populate
 76     spiral = [
 77           [1, 2, 3, 4, 5],
 78           [14, 15, 16, 17, 6],
 79           [13, 20, 19, 18, 7],
 80           [12, 11, 10, 9, 8]
 81          ]
 82     s = @spiral.populate
 83     assert_equal(spiral, s)
 84   end
 85 
 86   def test_change_directon_right
 87     @spiral.direction = :right
 88     @spiral.change_direction
 89     assert_equal(:down, @spiral.direction)
 90   end
 91 
 92   def test_change_directon_up
 93     @spiral.direction = :up
 94     @spiral.change_direction
 95     assert_equal(:right, @spiral.direction)
 96   end
 97 
 98   def test_next_cell_0_0
 99     x, y = @spiral.next_cell(0,0)
100     assert_equal(0, x)
101     assert_equal(1, y)
102   end
103 
104   def test_next_cell_0_4
105     x, y = @spiral.next_cell(0,4)
106     assert_equal(1, x)
107     assert_equal(4, y)
108   end
109 
110 end
111 

Ruby : Time Math Interview Problem With Bug Fixed (still writing test first)

While discussing my friend Arsalan's C# (seemlessly compiled on my linux machine using mcs)
solution and testing it out I found a bug in my own code that. The problem was when adding
more than 12 hours (> 720 minutes) it was not doing the right thing. The code can still be
refactored for cleaner solution but it is too late at night to do that now. Also, my wife
gave me another idea to convert the time to minutes before adding which I will try out later.

  1  # Without using any built in date or time functions, write a function or method
  2  # that accepts two mandatory arguments. The first argument is a string of the
  3  # format "[H]H:MM {AM|PM}" and the second argument is an integer. Assume the
  4  # integer is the number of minutes to add to the string. The return value of
  5  # the function should be a string of the same format as the first argument.
  6  # For example AddMinutes("9:13 AM", 10) would return "9:23 AM". The exercise
  7  # isn't meant to be too hard. I just want to see how you code. Feel free to
  8  # do it procedurally or in an object oriented way, whichever you prefer. Use
  9  # any language you want. Write production quality code. 
 10  # Question Source: http://blist.com/blog/
 11 
 12  # the following solution was developed using TDD
 13 
 14  require 'test/unit'
 15 
 16  class TestTimeCalc < Test::Unit::TestCase
 17 
 18      def setup
 19          @time = "9:13 AM"
 20      end
 21 
 22      def test_new_time_cal
 23          assert_not_nil(TimeCalc.new)
 24      end
 25 
 26      def test_add_minute_zero
 27          assert_equal(@time, TimeCalc.add_minutes(@time, 0))
 28      end
 29 
 30      def test_add_minute_ten
 31          assert_equal("9:23 AM", TimeCalc.add_minutes(@time, 10))
 32      end
 33 
 34      def test_add_minute_thirteen
 35          assert_equal("9:26 AM", TimeCalc.add_minutes(@time, 13))
 36      end
 37 
 38      def test_add_hour
 39          assert_equal("10:13 AM", TimeCalc.add_minutes(@time, 60))
 40      end
 41 
 42      def test_add_two_hours_fifteen_minutes
 43          assert_equal("11:28 AM", TimeCalc.add_minutes(@time, 135))
 44      end
 45 
 46      def test_add_past_meridiem
 47          # 785 minutes = 13 hours and 5 minutes
 48          assert_equal("10:18 PM", TimeCalc.add_minutes(@time, 785))
 49      end
 50 
 51      def test_alpha_hour_min_format_throws_exception
 52          assert_raise(ArgumentError) { TimeCalc.add_minutes("AB:CD AM", 10) }
 53      end
 54 
 55      def test_bad_meridiem_throws_exception
 56          assert_raise(ArgumentError) { TimeCalc.add_minutes("AB:CD TM", 10) }
 57      end
 58 
 59      def test_hr_greater_than_twelve
 60          assert_raise(ArgumentError) { TimeCalc.add_minutes("13:00 PM", 10) }
 61      end
 62 
 63      def test_min_greater_than_fifty_nine
 64          assert_raise(ArgumentError) { TimeCalc.add_minutes("12:60 PM", 10) }
 65      end
 66 
 67      def test_add_lot_of_minutes
 68        # 1000 minutes = 16 hours and 40 minutes
 69        assert_equal("1:53 AM", TimeCalc.add_minutes(@time, 1000))
 70      end
 71 
 72      def test_add_up_to_noon
 73        # 9:13 AM plus 2 hr 47 min (107)
 74        assert_equal("12:00 PM", TimeCalc.add_minutes(@time, 167))
 75      end
 76 
 77      def test_add_whole_lot_of_minutes
 78        # 9999 minutes = 166 hours and 39 minutes
 79        assert_equal("7:52 AM", TimeCalc.add_minutes(@time, 9999))
 80      end
 81 
 82  end # end class TestTimeCalc
 83 
 84  class TimeCalc
 85 
 86      def self.add_minutes(time, minutes)
 87        (hour, min, meridiem) = parse_time_string(time)
 88 
 89        hour_increment = (min + minutes)/60
 90        min_increment = (min + minutes)%60 - min
 91 
 92        while (hour + hour_increment > 12)
 93          meridiem = (meridiem == 'AM' ? 'PM' : 'AM')
 94          hour_increment -= 12
 95        end
 96 
 97        hour += hour_increment
 98        # special case for 12th hour
 99        meridiem = (meridiem == 'AM' ? 'PM' : 'AM') if hour == 12
100        min += min_increment
101 
102        hour.to_s + ":" + sprintf('%02d', min) + " " + meridiem
103      end
104 
105      private
106 
107      def self.parse_time_string(time)
108          raise ArgumentError unless (matches = time.match(/(\d{1,2}):(\d{1,2})\s+(\w{2})/))
109          matches = time.match(/^(\d{1,2}):(\d{1,2})\s+([A|P]M)$/)
110          hour = matches[1].to_i
111          min = matches[2].to_i
112          meridiem = matches[3]
113          raise ArgumentError unless (hour <= 12)
114          raise ArgumentError unless (min < 60)
115          return [hour, min, meridiem]
116      end
117  end # end class TimeCalc
118 
119 if __FILE__ == $0
120   puts TimeCalc.add_minutes(ARGV[0], ARGV[1].to_i)
121 end
122 

# vim colorscheme = delek