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137 lines
2.3 KiB
137 lines
2.3 KiB
class Solver
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def initialize(maze)
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@maze = maze
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end
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def solve(from, to)
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seen = Set.new(from)
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queue = [[from, 0]]
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current = queue.shift
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loop do
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location = current[0]
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break if location == to
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if seen.include?(location)
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current = queue.shift
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next
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end
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seen << location
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neighbors = maze
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.open_neighbors(location[0], location[1])
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.reject {|location| seen.include?(location) }
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queue.concat(neighbors.map {|location| [location, current[1] + 1] })
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return nil if queue.empty?
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current = queue.shift
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end
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current[1]
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end
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private
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attr_reader :maze
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end
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class Maze
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attr_reader :locations
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def initialize(input)
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@maze = Hash.new
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@locations = Hash.new
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x, y = 0, 0
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input.chars.each do |char|
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case char
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when /\d/
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@locations[char.to_i] = [x,y]
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char = ?.
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when "\n"
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x = -1
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y += 1
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else
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# no-op
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end
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@maze[[x,y]] = char
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x += 1
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end
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end
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def [](x,y)
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maze[[x,y]]
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end
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def open_neighbors(x, y)
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[[-1, 0],
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[ 1, 0],
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[ 0, -1],
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[ 0, 1]].map {|dx,dy|
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[x+dx, y+dy]
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}.select {|x,y|
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self[x,y] == ?.
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}
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end
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private
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attr_reader :maze
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end
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if __FILE__ == $0
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maze = Maze.new(ARGF.read)
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solver = Solver.new(maze)
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hash = maze.locations.to_a.combination(2).each.with_object({}) {|(a, b), hash|
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steps = solver.solve(a[1], b[1])
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hash[[a[0],b[0]]] = steps
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hash[[b[0],a[0]]] = steps
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}
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p maze
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.locations
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.map(&:first)
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.permutation
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.select {|route| route[0] == 0 }
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.map {|route| route + [0] }
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.map {|route|
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[route, route.each_cons(2).map {|a,b| hash[[a,b]] }.inject(:+)]
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}.sort_by(&:last)
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.first
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end
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require 'minitest'
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# require 'minitest/autorun'
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class TestMaze < Minitest::Test
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def test_maze
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maze = Maze.new(<<-MAZE)
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###########
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#0.1.....2#
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#.#######.#
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#4.......3#
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###########
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MAZE
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assert_equal [1,1], maze.locations[0]
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assert_equal [[2,1], [1,2]], maze.open_neighbors(1,1)
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end
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end
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class TestSolver < Minitest::Test
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def test_solver
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maze = Maze.new(<<-MAZE)
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###########
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#0.1.....2#
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#.#######.#
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#4.......3#
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###########
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MAZE
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solver = Solver.new(maze)
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assert_equal 2, solver.solve(maze.locations[0], maze.locations[4])
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end
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end
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