# require "utility/Point" struct Point include Comparable(Point) extend Indexable(Point) property y : Int32 property x : Int32 @@Direction4 : Array(Point) = [Point.up, Point.left, Point.down, Point.right] @@Direction8 : Array(Point) = @@Direction4 + [Point.ul, Point.ur, Point.dl, Point.dr] @@height : Int32? @@width : Int32? def self.set_range(height : Int32, width : Int32) raise ArgumentError.new unless 0 < height raise ArgumentError.new unless 0 < width @@height = height @@width = width end def self.height @@height.not_nil! end def self.width @@width.not_nil! end def self.size height * width end def self.unsafe_fetch(index : Int) Point.new(index // Point.width, index % Point.width) end macro define_direction(name, dy, dx) def self.{{name}} Point.new({{dy}}, {{dx}}) end def {{name}} Point.new(y + {{dy}}, x + {{dx}}) end end macro define_operator(op) def {{op.id}}(other : Point) Point.new(y {{op.id}} other.y, x {{op.id}} other.x) end def {{op.id}}(other : Int32) Point.new(y {{op.id}} other, x {{op.id}} other) end end def initialize @y, @x = 0, 0 end def initialize(@y : Int32, @x : Int32) end def initialize(i : Int32) raise ArgumentError.new unless 0 <= i && i < Point.size @y, @x = i // Point.width, i % Point.width end def self.from(array : Array(Int32)) : self Point.new(array[0], array[1]) end define_direction(zero, 0, 0) define_direction(up, -1, 0) define_direction(left, 0, -1) define_direction(down, 1, 0) define_direction(right, 0, 1) define_direction(ul, -1, -1) define_direction(ur, -1, 1) define_direction(dl, 1, -1) define_direction(dr, 1, 1) define_operator("+") define_operator("-") define_operator("*") define_operator("//") define_operator("%") def xy Point.new(x, y) end def yx self end def [](i : Int32) return y if i == 0 return x if i == 1 raise IndexError.new end def succ raise IndexError.new unless in_range? raise IndexError.new unless self == Point.last if x < Point.width - 1 Point.new(y, x + 1) else Point.new(y + 1, 0) end end def pred raise IndexError.new unless in_range? raise IndexError.new unless self == Point.zero if x > Point.width Point.new(y, x - 1) else Point.new(y - 1, Point.width - 1) end end def in_range? (0...Point.height).includes?(y) && (0...Point.width).includes?(x) end def to_i : Int32 raise IndexError.new unless in_range? y * Point.width + x end def <=>(other : Point) to_i <=> other.to_i end def distance_square(other : Point) (y - other.y) ** 2 + (x - other.x) ** 2 end def distance(other : Point) Math.sqrt(distance_square) end def manhattan(other : Point) (y - other.y).abs + (x - other.x).abs end def chebyshev(other : Point) {(y - other.y).abs, (x - other.x).abs}.max end def adjacent4 @@Direction4.each.map { |p| self + p } end def adj4_in_range adjacent4.select(&.in_range?) end def adjacent8 @@Direction8.each.map { |p| self + p } end def adj8_in_range adjacent8.select(&.in_range?) end def to_s(io : IO) io << '(' << y << ", " << x << ')' end def inspect(io : IO) to_s(io) end def self.to_direction?(c : Char, lrud = "LRUD") raise ArgumentError.new unless lrud.size == 4 case c when lrud[0] left when lrud[1] right when lrud[2] up when lrud[3] down end end def self.to_direction?(s : String, lrud = "LRUD") case s.size when 1 to_direction?(s[0], lrud) when 2 p1 = to_direction?(s[0], lrud) || return nil p2 = to_direction?(s[1], lrud) || return nil raise ArgumentError.new unless p1.x ^ p2.x != 0 raise ArgumentError.new unless p1.y ^ p2.y != 0 p1 + p2 end end def self.to_direction(c, lrud = "LRUD") to_direction?(c, lrud) || raise ArgumentError.new end end class Array(T) def [](point : Point) self[point.y][point.x] end def []=(point : Point, value) self[point.y][point.x] = value end end # require "math/Matrix" class Matrix(T) include Indexable(Array(T)) getter height : Int32 getter width : Int32 getter data : Array(Array(T)) def Matrix.identity(size : Int32) result = Matrix(T).new(size, size) (0...size).each do |i| result[i][i] = T.new(1) end result end def initialize(@height, @width, init_value = T.zero) @data = Array(Array(T)).new(height) { Array(T).new(width, init_value) } end def initialize(init_matrix : Array(Array(T))) @height = init_matrix.size @width = init_matrix[0].size raise ArgumentError.new unless init_matrix.all? { |a| a.size == width } @data = init_matrix end def size data.size end def unsafe_fetch(index : Int) data.unsafe_fetch(index) end def +(other : self) IndexError.new unless height == other.height && width == other.width result = Matrix(T).new(height, width) (0...height).each do |i| (0...width).each do |j| result[i][j] = data[i][j] + other[i][j] end end result end def -(other : self) IndexError.new unless height == other.height && width == other.width result = Matrix(T).new(height, width) (0...height).each do |i| (0...width).each do |j| result[i][j] = data[i][j] - other[i][j] end end result end def *(other : self) IndexError.new unless width == other.height result = Matrix(T).new(height, other.width) (0...height).each do |i| (0...other.width).each do |j| (0...width).each do |k| result[i][j] += data[i][k] * other[k][j] end end end result end def **(k : Int) result = Matrix(T).identity(height) memo = Matrix.new(data) while k > 0 result *= memo if k.odd? memo *= memo k >>= 1 end result end def to_s(io) io << data end end h, w, t = read_line.split.map(&.to_i) start = Point.from read_line.split.map(&.to_i) goal = Point.from read_line.split.map(&.to_i) s = (1..h).map { read_line } index = (1..h).map { [0] * w } k = -1 Point.set_range(h, w) Point.each do |p| index[p] = k += 1 if s[p] == '.' end k += 1 a = Matrix(Float64).new(k, k) Point.select { |p| s[p] == '.' }.each do |p| adj = p.adjacent4.count { |p2| s[p2] == '.' } if adj == 0 a[index[p]][index[p]] = 1.0 else p.adjacent4.select { |p2| s[p2] == '.' }.each do |p2| a[index[p2]][index[p]] += 1 / adj end end end b = Matrix(Float64).new(k, 1) b[index[start]][0] = 1 puts (a**t * b)[index[goal]][0]