def solve(io) n = io.get g = GraphW(Int32).new(n * 2 + 2) s, t = n * 2, n * 2 + 1 n.times do |i| g.add_edge(s, i, 1) g.add_edge(i + n, t, 1) ai, bi = io.get2; ai -= 1; bi -= 1 g.add_edge(i, ai + n, 1) g.add_edge(i, bi + n, 1) end ff = g.ford_fulkerson(s, t) io.put_e "No" unless ff.flow == n fg = ff.flow_graph io.put "Yes" n.times do |i| io.put fg[i][0].dst - n + 1 end end class ProconIO def initialize(@ins : IO = STDIN, @outs : IO = STDOUT) @buf = IO::Memory.new("") end def get(k : T.class = Int32) forall T get_v(k) end macro define_get {% for i in (2..9) %} def get({{ *(1..i).map { |j| "k#{j}".id } }}) { {{ *(1..i).map { |j| "get(k#{j})".id } }} } end {% end %} end define_get macro define_getn {% for i in (2..9) %} def get{{i}}(k : T.class = Int32) forall T get({{ *(1..i).map { "k".id } }}) end {% end %} end define_getn def get_a(n : Int, k : T.class = Int32) forall T Array.new(n) { get_v(k) } end def get_c(n : Int, k : T.class = Int32) forall T get_a(n, k) end macro define_get_c {% for i in (2..9) %} def get_c(n : Int, {{ *(1..i).map { |j| "k#{j}".id } }}) a = Array.new(n) { get({{ *(1..i).map { |j| "k#{j}".id } }}) } { {{ *(1..i).map { |j| "a.map { |e| e[#{j-1}] }".id } }} } end {% end %} end define_get_c macro define_getn_c {% for i in (2..9) %} def get{{i}}_c(n : Int, k : T.class = Int32) forall T get_c(n, {{ *(1..i).map { "k".id } }}) end {% end %} end define_getn_c def get_m(r : Int, c : Int, k : T.class = Int32) forall T Array.new(r) { get_a(c, k) } end macro define_put {% for i in (1..9) %} def put({{ *(1..i).map { |j| "v#{j}".id } }}, *, delimiter = " ") {% for j in (1..i) %} print_v(v{{j}}, delimiter) {% if j < i %}@outs << delimiter{% end %} {% end %} @outs.puts end {% end %} end define_put def put_e(*vs) put(*vs) exit end def put_f(*vs) put(*vs) @outs.flush end private def get_v(k : Int32.class); get_token.to_i32; end private def get_v(k : Int64.class); get_token.to_i64; end private def get_v(k : UInt32.class); get_token.to_u32; end private def get_v(k : UInt64.class); get_token.to_u64; end private def get_v(k : Float64.class); get_token.to_f64; end private def get_v(k : String.class); get_token; end private def get_token loop do token = @buf.gets(' ', chomp: true) break token unless token.nil? @buf = IO::Memory.new(@ins.read_line) end end private def print_v(v, dlimiter) @outs << v end private def print_v(v : Enumerable, delimiter) v.each_with_index do |e, i| @outs << e @outs << delimiter if i < v.size - 1 end end end struct Int def cdiv(b : Int) (self + b - 1) // b end def bit?(i : Int) bit(i) == 1 end def set_bit(i : Int) self | (self.class.new(1) << i) end def reset_bit(i : Int) self & ~(self.class.new(1) << i) end {% if compare_versions(env("CRYSTAL_VERSION") || "0.0.0", "0.35.0") < 0 %} def digits(base = 10) raise ArgumentError.new("Invalid base #{base}") if base < 2 raise ArgumentError.new("Can't request digits of negative number") if self < 0 return [0] if self == 0 num = self digits_count = (Math.log(self.to_f + 1) / Math.log(base)).ceil.to_i ary = Array(Int32).new(digits_count) while num != 0 ary << num.remainder(base).to_i num = num.tdiv(base) end ary end {% end %} {% if compare_versions(env("CRYSTAL_VERSION") || "0.0.0", "0.34.0") < 0 %} def bit_length : Int32 x = self < 0 ? ~self : self if x.is_a?(Int::Primitive) Int32.new(sizeof(self) * 8 - x.leading_zeros_count) else to_s(2).size end end {% end %} end struct Float64 def near?(x) (self - x).abs <= (self.abs < x.abs ? x.abs : self.abs) * EPSILON end end struct Number {% if compare_versions(env("CRYSTAL_VERSION") || "0.0.0", "1.1.0") < 0 %} def zero? self == 0 end def positive? self > 0 end def negative? self < 0 end {% end %} {% if compare_versions(env("CRYSTAL_VERSION") || "0.0.0", "0.36.0") < 0 %} def self.additive_identity zero end def self.multiplicative_identity new(1) end {% end %} end class Array macro new_md(*args, &block) {% if !block %} {% for arg, i in args[0...-2] %} Array.new({{arg}}) { {% end %} Array.new({{args[-2]}}, {{args[-1]}}) {% for arg in args[0...-2] %} } {% end %} {% else %} {% for arg, i in args %} Array.new({{arg}}) { |_i{{i}}| {% end %} {% for block_arg, i in block.args %} {{block_arg}} = _i{{i}} {% end %} {{block.body}} {% for arg in args %} } {% end %} {% end %} end end module Math {% if compare_versions(env("CRYSTAL_VERSION") || "0.0.0", "1.2.0") < 0 %} def isqrt(value : Int::Primitive) raise ArgumentError.new "Input must be non-negative integer" if value < 0 return value if value < 2 res = value.class.zero bit = res.succ << (res.leading_zeros_count - 2) bit >>= value.leading_zeros_count & ~0x3 while (bit != 0) if value >= res + bit value -= res + bit res = (res >> 1) + bit else res >>= 1 end bit >>= 2 end res end {% end %} end macro min_u(a, b) {{a}} = Math.min({{a}}, {{b}}) end macro max_u(a, b) {{a}} = Math.max({{a}}, {{b}}) end macro zip(a, *b, &block) {{a}}.zip({{*b}}) {{block}} end require "bit_array" class Graph alias Node = Int32 def initialize(@size : Node) @g = Array(Array(Node)).new(@size) { [] of Node } end getter size : Int32 delegate :[], to: @g def add_edge(u : Node, v : Node) @g[u] << v end def add_edge_b(u : Node, v : Node) @g[u] << v @g[v] << u end def bfs(u : Node) b = BitArray.new(@size) yield u, -1 b[u] = true q = Deque.new([u]) until q.empty? v = q.shift @g[v].each do |w| next if b[w] yield w, v b[w] = true q.push(w) end end end end class GraphW(T) alias Node = Int32 struct Edge(T) def initialize(@src : Node, @dst : Node, @wt : T) end getter src : Node, dst : Node getter wt : T end def initialize(@size : Node, @inf = 10**9) @g = Array(Array(Edge(T))).new(@size) { [] of Edge(T) } end getter size : Int32 getter inf : T delegate :[], to: @g def add_edge(u : Node, v : Node, wt : T) @g[u] << Edge.new(u, v, wt) end def add_edge_b(u : Node, v : Node, wt : T) @g[u] << Edge.new(u, v, wt) @g[v] << Edge.new(v, u, wt) end end class GraphM(T) alias Node = Int32 def initialize(@size : Int32, @inf = 10**9) @g = Array.new_md(@size, @size, @inf) @size.times do |i| @g[i][i] = T.zero end end getter size : Int32 getter inf : T delegate :[], to: @g def add_edge(u : Node, v : Node, wt : T) @g[u][v] = wt end def add_edge_b(u : Node, v : Node, wt : T) @g[u][v] = @g[v][u] = wt end @g : Array(Array(T)) end class FordFulkerson(T) alias Node = GraphW::Node def initialize(@g : GraphW(T), s : Node, t : Node) @adj = build_adj visited = Array.new(@g.size, false) @flow = T.zero augment = uninitialized Node, T -> T augment = ->(u : Node, cur : T) do return cur if u == t visited[u] = true @adj[u].each do |e| if !visited[e.dst] && e.cap > e.flow f = augment.call(e.dst, {e.cap - e.flow, cur}.min) if f > T.zero e.flow += f @adj[e.dst][e.rev].flow -= f return f end end end T.zero end loop do visited.fill(false) f = augment.call(s, @g.inf) break if f == 0 @flow += f end end getter flow : T def flow_graph g = GraphW(T).new(@g.size, @g.inf) @g.size.times do |i| @adj[i].each do |e| if e.flow > T.zero g.add_edge(e.src, e.dst, e.flow) end end end g end class EdgeR(T) def initialize(@src : Node, @dst : Node, @cap : T, @flow : T, @rev : Node) end getter src, dst, cap, rev property flow end def build_adj adj = Array.new(@g.size) { [] of EdgeR(T) } @g.size.times do |i| @g[i].each do |e| adj[e.src] << EdgeR.new(e.src, e.dst, e.wt, T.zero, adj[e.dst].size) adj[e.dst] << EdgeR.new(e.dst, e.src, T.zero, T.zero, adj[e.src].size - 1) end end adj end @adj : Array(Array(EdgeR(T))) end class GraphW(T) def ford_fulkerson(s, t) FordFulkerson.new(self, s, t) end end solve(ProconIO.new)