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require "../graph" # Example of `T`: # ``` # struct DP # getter val : Int64, cnt : Int32 # # def initialize # @val, @cnt = 0i64, 0 # end # # def initialize(@val, @cnt) # end # # def +(other : self) : self # DP.new(val + other.val, cnt + other.cnt) # end # # def add_root(v : Int32) : self # DP.new(val + cnt, cnt + 1) # end # end # ``` class ReRooting(T, GraphType) getter graph : GraphType def initialize(size : Int) initialize(GraphType.new(size)) end def initialize(@graph : GraphType) @dp = Array(Array(T)).new @result = Array(T).new end def initialize(size : Int, edges : Enumerable) initialize(GraphType.new(size, edges)) end delegate size, :<<, add_edges, to: @graph private def dfs(v : Int32, p : Int32) : T acc = T.new graph[v].each_with_index do |edge, i| if edge.to != p acc += (@dp[v][i] = dfs(edge.to, v)) end end acc.add_root(v) end private def bfs(v : Int32, p : Int32, dp_p : T) : Nil graph[v].each_with_index do |edge, i| @dp[v][i] = dp_p if edge.to == p end n = graph[v].size dp_left = Array.new(n + 1, T.new) (0...n).each do |i| dp_left[i + 1] = dp_left[i] + @dp[v][i] end dp_right = Array.new(n + 1, T.new) (0...n).reverse_each do |i| dp_right[i] = dp_right[i + 1] + @dp[v][i] end @result[v] = dp_left.last.add_root(v) graph[v].each_with_index do |edge, i| bfs(edge.to, v, (dp_left[i] + dp_right[i + 1]).add_root(v)) if edge.to != p end end def solve : Array(T) @dp = Array.new(size) { |i| Array.new(@graph[i].size, T.new) } @result = Array.new(size, T.new) dfs(0, -1) bfs(0, -1, T.new) @result end end
# require "../graph" # require "./graph/edge" struct WeightedEdge(T) include Comparable(WeightedEdge(T)) property to : Int32, cost : T def initialize(@to, @cost : T) end def <=>(other : WeightedEdge(T)) {cost, to} <=> {other.cost, other.to} end def to_s(io) : Nil io << '(' << to << ", " << cost << ')' end def inspect(io) : Nil io << "->" << to << '(' << cost << ')' end end struct WeightedEdge2(T) include Comparable(WeightedEdge2(T)) property from : Int32, to : Int32, cost : T def initialize(@from, @to, @cost : T) end def initialize(@from, edge : WeightedEdge(T)) @to, @cost = edge.to, edge.cost end def <=>(other : WeightedEdge2(T)) {cost, from, to} <=> {other.cost, other.from, other.to} end def reverse : self WeightedEdge2(T).new(to, from, cost) end def sort : self WeightedEdge2(T).new(*{to, from}.minmax, cost) end def to_s(io) : Nil io << '(' << from << ", " << to << ", " << cost << ')' end def inspect(io) : Nil io << from << "->" << to << '(' << cost << ')' end end struct UnweightedEdge property to : Int32 def initialize(@to) end def initialize(@to, cost) end def cost : Int32 1 end def to_s(io) : Nil io << to end def inspect(io) : Nil io << "->" << to end end struct UnweightedEdge2 property from : Int32, to : Int32 def initialize(@from, @to) end def initialize(@from, @to, cost) end def initialize(@from, edge : UnweightedEdge) @to = edge.to end def cost : Int32 1 end def reverse : self UnweightedEdge2.new(to, from) end def sort : self UnweightedEdge2.new(*{to, from}.minmax) end def to_s(io) : Nil io << '(' << from << ", " << to << ')' end def inspect(io) : Nil io << from << "->" << to end end module Graph(Edge, Edge2) include Enumerable(Edge2) getter graph : Array(Array(Edge)) def initialize(size : Int) @graph = Array(Array(Edge)).new(size) { [] of Edge } end def initialize(size : Int, edges : Enumerable) initialize(size) add_edges(edges) end # Add *edge*. abstract def <<(edge : Edge2) # :ditto: def <<(edge : Tuple) : self self << Edge2.new(*edge) end def add_edges(edges : Enumerable) : self edges.each { |edge| self << edge } self end delegate size, :[], to: @graph # Yields each edge of the graph, ans returns `nil`. def each(&) : Nil (0...size).each do |v| graph[v].each do |edge| yield Edge2.new(v, edge) end end end def each_child(vertex : Int, parent, &block) : Nil graph[vertex].each do |edge| yield edge if edge.to != parent end end def each_child(vertex : Int, parent) graph[vertex].each.reject(&.to.== parent) end def reverse : self if self.class.directed? each_with_object(self.class.new(size)) do |edge, reversed| reversed << edge.reverse end else dup end end def to_undirected : self if self.class.directed? each_with_object(self.class.new(size)) do |edge, graph| graph << edge << edge.reverse end else dup end end def to_s(io : IO) : Nil io << '[' join(", ", io) do |edge, io| edge.inspect io end io << ']' end def inspect(io : IO) : Nil io << "[\n" graph.each do |edges| io << " " << edges << ",\n" end io << ']' end end class DiGraph(T) include Graph(WeightedEdge(T), WeightedEdge2(T)) def self.weighted? true end def self.directed? true end def initialize(size : Int) super end def initialize(size : Int, edges : Enumerable(WeightedEdge2(T))) super end def initialize(size : Int, edges : Enumerable({Int32, Int32, T})) super end def <<(edge : WeightedEdge2(T)) : self raise IndexError.new unless 0 <= edge.from < size && 0 <= edge.to < size @graph[edge.from] << WeightedEdge.new(edge.to, edge.cost) self end end class UnGraph(T) include Graph(WeightedEdge(T), WeightedEdge2(T)) def self.weighted? true end def self.directed? false end def initialize(size : Int) super end def initialize(size : Int, edges : Enumerable(WeightedEdge2(T))) super end def initialize(size : Int, edges : Enumerable({Int32, Int32, T})) super end def <<(edge : WeightedEdge2(T)) : self raise IndexError.new unless 0 <= edge.from < size && 0 <= edge.to < size @graph[edge.from] << WeightedEdge.new(edge.to, edge.cost) @graph[edge.to] << WeightedEdge.new(edge.from, edge.cost) self end end class UnweightedDiGraph include Graph(UnweightedEdge, UnweightedEdge2) def self.weighted? false end def self.directed? true end def initialize(size : Int) super end def initialize(size : Int, edges : Enumerable) super end def <<(edge : UnweightedEdge2) : self raise IndexError.new unless 0 <= edge.from < size && 0 <= edge.to < size @graph[edge.from] << UnweightedEdge.new(edge.to) self end end class UnweightedUnGraph include Graph(UnweightedEdge, UnweightedEdge2) def self.weighted? false end def self.directed? false end def initialize(size : Int) super end def initialize(size : Int, edges : Enumerable) super end def <<(edge : UnweightedEdge2) : self raise IndexError.new unless 0 <= edge.from < size && 0 <= edge.to < size @graph[edge.from] << UnweightedEdge.new(edge.to) @graph[edge.to] << UnweightedEdge.new(edge.from) self end end # Example of `T`: # ``` # struct DP # getter val : Int64, cnt : Int32 # # def initialize # @val, @cnt = 0i64, 0 # end # # def initialize(@val, @cnt) # end # # def +(other : self) : self # DP.new(val + other.val, cnt + other.cnt) # end # # def add_root(v : Int32) : self # DP.new(val + cnt, cnt + 1) # end # end # ``` class ReRooting(T, GraphType) getter graph : GraphType def initialize(size : Int) initialize(GraphType.new(size)) end def initialize(@graph : GraphType) @dp = Array(Array(T)).new @result = Array(T).new end def initialize(size : Int, edges : Enumerable) initialize(GraphType.new(size, edges)) end delegate size, :<<, add_edges, to: @graph private def dfs(v : Int32, p : Int32) : T acc = T.new graph[v].each_with_index do |edge, i| if edge.to != p acc += (@dp[v][i] = dfs(edge.to, v)) end end acc.add_root(v) end private def bfs(v : Int32, p : Int32, dp_p : T) : Nil graph[v].each_with_index do |edge, i| @dp[v][i] = dp_p if edge.to == p end n = graph[v].size dp_left = Array.new(n + 1, T.new) (0...n).each do |i| dp_left[i + 1] = dp_left[i] + @dp[v][i] end dp_right = Array.new(n + 1, T.new) (0...n).reverse_each do |i| dp_right[i] = dp_right[i + 1] + @dp[v][i] end @result[v] = dp_left.last.add_root(v) graph[v].each_with_index do |edge, i| bfs(edge.to, v, (dp_left[i] + dp_right[i + 1]).add_root(v)) if edge.to != p end end def solve : Array(T) @dp = Array.new(size) { |i| Array.new(@graph[i].size, T.new) } @result = Array.new(size, T.new) dfs(0, -1) bfs(0, -1, T.new) @result end end