require "set" require "minitest" require "minitest/pride" class Slice def self.parse(s) squares = {} s.scan(/^(x|y)=(\d+), (?:x|y)=(\d+)..(\d+)$/m).each do |xy, i, min, max| i, min, max = [i, min, max].map(&:to_i) (min..max).map {|j| xy == ?x ? [i, j] : [j, i] }.each do |pos| squares[pos] = ?# end end new(squares) end def initialize(squares) @squares = squares @squares[[500, 0]] = ?+ @active = Set[[500, 0]] end def simulate return enum_for(__method__) unless block_given? max_y = @squares.keys.map(&:last).max loop do settled = [] @active.to_a.each do |pos| @active.delete(pos) x, y = pos case @squares.fetch(pos) when ?+ @squares[[x, y+1]] = ?| @active << [x, y+1] when ?| if @squares[[x, y+1]].nil? if y+1 <= max_y @squares[[x, y+1]] = ?| @active << [x, y+1] end else left = @squares[[x-1, y]].nil? right = @squares[[x+1, y]].nil? if !left && !right settled << [x, y] end if left @squares[[x-1, y]] = ?| @active << [x-1, y] end if right @squares[[x+1, y]] = ?| @active << [x+1, y] end end end end if @active.empty? while pos = settled.shift @squares[pos] = ?~ if @squares[pos] == ?| x, y = pos @active << [x, y-1] if @squares[[x, y-1]] == ?| settled << [x-1, y] if @squares[[x-1, y]] == ?| settled << [x+1, y] if @squares[[x+1, y]] == ?| end end yield self end end def water end def to_s min_x, max_x = @squares.keys.map(&:first).minmax min_y, max_y = @squares.keys.map(&:last).minmax min_y = [0, min_y].min (min_y..max_y).map {|y| (min_x-1..max_x+1).map {|x| @squares.fetch([x, y]) { ?. } }.join }.join(?\n) end end class TestSlice < Minitest::Test def setup @slice = Slice.parse(<<~SLICE) x=495, y=2..7 y=7, x=495..501 x=501, y=3..7 x=498, y=2..4 x=506, y=1..2 x=498, y=10..13 x=504, y=10..13 y=13, x=498..504 SLICE end def test_parse_to_s assert_equal <<~SLICE.chomp, @slice.to_s ......+....... ............#. .#..#.......#. .#..#..#...... .#..#..#...... .#.....#...... .#.....#...... .#######...... .............. .............. ....#.....#... ....#.....#... ....#.....#... ....#######... SLICE end def test_simulate simulation = @slice.simulate slice = 5.times { simulation.next } assert_equal <<~SLICE.chomp, @slice.to_s ......+....... ......|.....#. .#..#.|.....#. .#..#.|#...... .#..#.|#...... .#....|#...... .#.....#...... .#######...... .............. .............. ....#.....#... ....#.....#... ....#.....#... ....#######... SLICE slice = 6.times { simulation.next } assert_equal <<~SLICE.chomp, @slice.to_s ......+....... ......|.....#. .#..#.|.....#. .#..#.|#...... .#..#.|#...... .#....|#...... .#~~~~~#...... .#######...... .............. .............. ....#.....#... ....#.....#... ....#.....#... ....#######... SLICE slice = 5.times { simulation.next } assert_equal <<~SLICE.chomp, @slice.to_s ......+....... ......|.....#. .#..#.|.....#. .#..#.|#...... .#..#.|#...... .#~~~~~#...... .#~~~~~#...... .#######...... .............. .............. ....#.....#... ....#.....#... ....#.....#... ....#######... SLICE slice = 4.times { simulation.next } assert_equal <<~SLICE.chomp, @slice.to_s ......+....... ......|.....#. .#..#.|.....#. .#..#~~#...... .#..#~~#...... .#~~~~~#...... .#~~~~~#...... .#######...... .............. .............. ....#.....#... ....#.....#... ....#.....#... ....#######... SLICE slice = 24.times { simulation.next } assert_equal <<~SLICE.chomp, @slice.to_s ......+....... ......|.....#. .#..#||||...#. .#..#~~#|..... .#..#~~#|..... .#~~~~~#|..... .#~~~~~#|..... .#######|..... ........|..... ........|..... ....#~~~~~#... ....#~~~~~#... ....#~~~~~#... ....#######... SLICE slice = 9.times { simulation.next } assert_equal <<~SLICE.chomp, @slice.to_s ......+....... ......|.....#. .#..#||||...#. .#..#~~#|..... .#..#~~#|..... .#~~~~~#|..... .#~~~~~#|..... .#######|..... ........|..... ...|||||||||.. ...|#~~~~~#|.. ...|#~~~~~#|.. ...|#~~~~~#|.. ...|#######|.. SLICE end end def solve(input) end if __FILE__ == $0 require "minitest/autorun" and exit if ENV["TEST"] puts solve(ARGF.read) end