#695137 (Crystal) No.1665 quotient replace

提出ソース
結果

問題	No.1665 quotient replace
ユーザー	yuruhiya
提出日時	2021-09-03 21:30:21
言語	Crystal (1.11.2)
結果	AC
実行時間	2,769 ms / 3,000 ms
コード長	20,339 bytes
コンパイル時間	23,103 ms
コンパイル使用メモリ	260,644 KB
実行使用メモリ	80,436 KB
最終ジャッジ日時	2023-08-21 19:50:49
合計ジャッジ時間	54,488 ms
ジャッジサーバーID （参考情報）	judge13 / judge11
このコードへのチャレンジ（β）
テストケース

テストケース表示
入力	結果	実行時間実行使用メモリ
testcase_00	AC	3 ms 4,408 KB
testcase_01	AC	2 ms 4,388 KB
testcase_02	AC	3 ms 4,380 KB
testcase_03	AC	5 ms 4,700 KB
testcase_04	AC	4 ms 4,604 KB
testcase_05	AC	3 ms 4,384 KB
testcase_06	AC	24 ms 5,680 KB
testcase_07	AC	7 ms 4,900 KB
testcase_08	AC	15 ms 5,380 KB
testcase_09	AC	86 ms 7,164 KB
testcase_10	AC	923 ms 34,232 KB
testcase_11	AC	2,145 ms 60,928 KB
testcase_12	AC	227 ms 12,096 KB
testcase_13	AC	2,765 ms 80,388 KB
testcase_14	AC	2,760 ms 80,292 KB
testcase_15	AC	2,765 ms 80,292 KB
testcase_16	AC	2,761 ms 80,240 KB
testcase_17	AC	2,769 ms 80,436 KB
testcase_18	AC	2 ms 4,416 KB
testcase_19	AC	3 ms 4,384 KB
testcase_20	AC	2 ms 4,380 KB
testcase_21	AC	2 ms 4,388 KB
testcase_22	AC	2 ms 4,456 KB
testcase_23	AC	3 ms 4,388 KB
testcase_24	AC	2 ms 4,384 KB
testcase_25	AC	2 ms 4,380 KB
testcase_26	AC	5 ms 4,960 KB
testcase_27	AC	10 ms 5,304 KB
testcase_28	AC	38 ms 7,560 KB
testcase_29	AC	74 ms 10,428 KB
testcase_30	AC	526 ms 49,304 KB
testcase_31	AC	798 ms 78,800 KB
testcase_32	AC	1,998 ms 61,016 KB
testcase_33	AC	736 ms 27,184 KB
testcase_34	AC	1,593 ms 49,136 KB
testcase_35	AC	1,439 ms 49,328 KB
testcase_36	AC	1,522 ms 49,276 KB
testcase_37	AC	1,385 ms 49,364 KB
testcase_38	AC	1,664 ms 61,220 KB
testcase_39	AC	1,146 ms 44,472 KB
testcase_40	AC	1,145 ms 44,456 KB
testcase_41	AC	1,145 ms 44,456 KB
testcase_42	AC	2 ms 4,380 KB
testcase_43	AC	3 ms 4,428 KB
権限があれば一括ダウンロードができます
ソースコード

raw source code
# require "/template"
# require "./tuple/times"
struct Tuple
  def times(&block) : Nil
    {% begin %}
      {% for i in 0...@type.size %}
        {% if @type[i].has_method?(:each) %}
          self[{{i}}].each do |i{{i}}|
        {% else %}
          self[{{i}}].times do |i{{i}}|
        {% end %}
      {% end %}
      yield({% for i in 0...@type.size %} i{{i}}, {% end %})
      {% for i in 0...@type.size %} end {% end %}
    {% end %}
  end

  private class TimesIterator(T)
    include Iterator(T)

    def initialize(@n : T)
      tuple = {% begin %}
                { {% for i in 0...T.size %} T[{{i}}].zero, {% end %} }
              {% end %}
      @index = tuple.as(T)
      @first = true
    end

    def next
      if @first
        @first = false
        return @index
      end
      {% begin %}
        {%
          type = @type.type_vars[0]
          size = type.size
        %}
        {% for i in 1..size %}
          if @index[{{size - i}}] < @n[{{size - i}}] - 1
            @index = {
              {% for j in 0...size %}
                {% if j < size - i %}
                  @index[{{j}}],
                {% elsif j == size - i %}
                  @index[{{j}}] + 1,
                {% else %}
                  {{type[j]}}.zero,
                {% end %}
              {% end %}
            }
            return @index
          end
        {% end %}
        stop
      {% end %}
    end
  end

  def times
    TimesIterator(self).new(self)
  end
end

# require "./comparable/min_max"
module Comparable(T)
  def min(x : T)
    self > x ? x : self
  end

  def max(x : T)
    self < x ? x : self
  end
end

# require "./array/new"
class Array
  def self.new(sizes : Tuple(*T), initial_value) forall T
    {% begin %}
      {% for i in 0...T.size %} Array.new(sizes[{{i}}]) { {% end %}
      initial_value
      {% for i in 0...T.size %} } {% end %}
    {% end %}
  end

  def self.new(sizes : Tuple(*T), &block) forall T
    {% begin %}
      {% for i in 0...T.size %} Array.new(sizes[{{i}}]) { |index{{i}}| {% end %}
      yield({% for i in 0...T.size %} index{{i}}, {% end %})
      {% for i in 0...T.size %} } {% end %}
    {% end %}
  end
end

# require "./array/change"
class Array(T)
  def chmin(i : Int, value : T)
    (self[i] > value).tap do |f|
      self[i] = value if f
    end
  end

  protected def chmin(i : Int, *indexes, value)
    self[i].chmin(*indexes, value: value)
  end

  def chmin(indexes : Tuple, value)
    chmin(*indexes, value: value)
  end

  def chmax(i : Int, value : T)
    (self[i] < value).tap do |f|
      self[i] = value if f
    end
  end

  protected def chmax(i : Int, *indexes, value)
    self[i].chmax(*indexes, value: value)
  end

  def chmax(indexes : Tuple, value)
    chmax(*indexes, value: value)
  end
end

# require "./scanner"
# ### Specifications
#
# ```plain
# Inside input macro                   | Expanded code
# -------------------------------------+---------------------------------------
# Uppercase string: Int32, Int64, etc. | {}.new(Scanner.s)
# s                                    | Scanner.s
# c                                    | Scanner.c
# Other lowercase string: i, i64, etc. | Scanner.s.to_{}
# operator[]: type[size]               | Array.new(input(size)) { input(type) }
# Tuple literal: {t1, t2, t3}          | {input(t1), input(t2), input(t3)}
# Array literal: [t1, t2, t3]          | [input(t1), input(t2), input(t3)]
# Range literal: t1..t2                | input(t1)..input(t2)
# If: cond ? t1 : t2                   | cond ? input(t1) : input(t2)
# Assign: target = value               | target = input(value)
# ```
#
# ### Examples
#
# Input:
# ```plain
# 5 3
# foo bar
# 1 2 3 4 5
# ```
# ```
# n, m = input(Int32, Int64) # => {5, 10i64}
# input(String, Char[m])     # => {"foo", ['b', 'a', 'r']}
# input(Int32[n])            # => [1, 2, 3, 4, 5]
# ```
# ```
# n, m = input(i, i64) # => {5, 10i64}
# input(s, c[m])       # => {"foo", ['b', 'a', 'r']}
# input(i[n])          # => [1, 2, 3, 4, 5]
# ```
#
# Input:
# ```plain
# 2 3
# 1 2 3
# 4 5 6
# ```
#
# ```
# h, w = input(i, i) # => {2, 3}
# input(i[h, w])     # => [[1, 2, 3], [4, 5, 6]]
# ```
# ```
# input(i[i][i]) # => [[1, 2, 3], [4, 5, 6]]
# ```
#
# Input:
# ```plain
# 5 3
# 3 1 4 2 5
# 1 2
# 2 3
# 3 1
# ```
# ```
# n, m = input(i, i)       # => {5, 3}
# input(i.pred[n])         # => [2, 0, 3, 1, 4]
# input({i - 1, i - 1}[m]) # => [{0, 1}, {1, 2}, {2, 0}]
# ```
#
# Input:
# ```plain
# 3
# 1 2
# 2 2
# 3 2
# ```
# ```
# input({tmp = i, tmp == 1 ? i : i.pred}[i]) # => [{1, 2}, {2, 1}, {3, 1}]
# ```
#
# Input:
# ```plain
# 3
# 1 2
# 2 3
# 3 1
# ```
# ```
# n = input(i)
# input_column({Int32, Int32}, n) # => {[1, 2, 3], [2, 3, 1]}
# ```
class Scanner
  private def self.skip_to_not_space
    peek = STDIN.peek
    not_space = peek.index { |x| x != 32 && x != 10 } || peek.size
    STDIN.skip(not_space)
  end

  def self.c
    skip_to_not_space
    STDIN.read_char.not_nil!
  end

  def self.s
    skip_to_not_space

    peek = STDIN.peek
    if index = peek.index { |x| x == 32 || x == 10 }
      STDIN.skip(index + 1)
      return String.new(peek[0, index])
    end

    String.build do |buffer|
      loop do
        buffer.write peek
        STDIN.skip(peek.size)
        peek = STDIN.peek
        break if peek.empty?
        if index = peek.index { |x| x == 32 || x == 10 }
          buffer.write peek[0, index]
          STDIN.skip(index)
          break
        end
      end
    end
  end
end

macro internal_input(type, else_ast)
  {% if Scanner.class.has_method?(type.id) %}
    Scanner.{{type.id}}
  {% elsif type.stringify == "String" %}
    Scanner.s
  {% elsif type.stringify == "Char" %}
    Scanner.c
  {% elsif type.stringify =~ /[A-Z][a-z0-9_]*/ %}
    {{type.id}}.new(Scanner.s)
  {% elsif String.has_method?("to_#{type}".id) %}
    Scanner.s.to_{{type.id}}
  {% else %}
    {{else_ast}}
  {% end %}
end

macro internal_input_array(type, args)
  {% for i in 0...args.size %}
    %size{i} = input({{args[i]}})
  {% end %}
  {% begin %}
    {% for i in 0...args.size %} Array.new(%size{i}) { {% end %}
      input({{type.id}})
    {% for i in 0...args.size %} } {% end %}
  {% end %}
end

macro input(type)
  {% if type.is_a?(Call) %}
    {% if type.receiver.is_a?(Nop) %}
      internal_input(
        {{type.name}}, {{type.name}}(
          {% for argument in type.args %} input({{argument}}), {% end %}
        )
      )
    {% elsif type.name.stringify == "[]" %}
      internal_input_array({{type.receiver}}, {{type.args}})
    {% else %}
      input({{type.receiver}}).{{type.name.id}}(
        {% for argument in type.args %} input({{argument}}), {% end %}
      ) {{type.block}}
    {% end %}
  {% elsif type.is_a?(TupleLiteral) %}
    { {% for i in 0...type.size %} input({{type[i]}}), {% end %} }
  {% elsif type.is_a?(ArrayLiteral) %}
    [ {% for i in 0...type.size %} input({{type[i]}}), {% end %} ]
  {% elsif type.is_a?(RangeLiteral) %}
    Range.new(input({{type.begin}}), input({{type.end}}), {{type.excludes_end?}})
  {% elsif type.is_a?(If) %}
    {{type.cond}} ? input({{type.then}}) : input({{type.else}})
  {% elsif type.is_a?(Assign) %}
    {{type.target}} = input({{type.value}})
  {% else %}
    internal_input({{type.id}}, {{type.id}})
  {% end %}
end

macro input(*types)
  { {% for type in types %} input({{type}}), {% end %} }
end

macro input_column(types, size)
  {% for type, i in types %}
    %array{i} = Array({{type}}).new({{size}})
  {% end %}
  {{size}}.times do
    {% for type, i in types %}
      %array{i} << input({{type}})
    {% end %}
  end
  { {% for type, i in types %} %array{i}, {% end %} }
end

# require "atcoder/Prime"
# ac-library.cr by hakatashi https://github.com/google/ac-library.cr
#
# Copyright 2021 Google LLC
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#      https://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.

# require "./Math.cr"
# ac-library.cr by hakatashi https://github.com/google/ac-library.cr
#
# Copyright 2021 Google LLC
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#      https://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.

module AtCoder
  # Implements [ACL's Math library](https://atcoder.github.io/ac-library/master/document_en/math.html)
  module Math
    def self.extended_gcd(a, b)
      last_remainder, remainder = a.abs, b.abs
      x, last_x, y, last_y = 0_i64, 1_i64, 1_i64, 0_i64
      while remainder != 0
        new_last_remainder = remainder
        quotient, remainder = last_remainder.divmod(remainder)
        last_remainder = new_last_remainder
        x, last_x = last_x - quotient * x, x
        y, last_y = last_y - quotient * y, y
      end

      return last_remainder, last_x * (a < 0 ? -1 : 1)
    end

    # Implements atcoder::inv_mod(value, modulo).
    def self.inv_mod(value, modulo)
      gcd, inv = extended_gcd(value, modulo)
      if gcd != 1
        raise ArgumentError.new("#{value} and #{modulo} are not coprime")
      end
      inv % modulo
    end

    # Simplified AtCoder::Math.pow_mod with support of Int64
    def self.pow_mod(base, exponent, modulo)
      if exponent == 0
        return base.class.zero + 1
      end
      if base == 0
        return base
      end
      b = exponent > 0 ? base : inv_mod(base, modulo)
      e = exponent.abs
      ret = 1_i64
      while e > 0
        if e % 2 == 1
          ret = mul_mod(ret, b, modulo)
        end
        b = mul_mod(b, b, modulo)
        e //= 2
      end
      ret
    end

    # Caluculates a * b % mod without overflow detection
    @[AlwaysInline]
    def self.mul_mod(a : Int64, b : Int64, mod : Int64)
      if mod < Int32::MAX
        return a * b % mod
      end

      # 31-bit width
      a_high = (a >> 32).to_u64
      # 32-bit width
      a_low = (a & 0xFFFFFFFF).to_u64
      # 31-bit width
      b_high = (b >> 32).to_u64
      # 32-bit width
      b_low = (b & 0xFFFFFFFF).to_u64

      # 31-bit + 32-bit + 1-bit = 64-bit
      c = a_high * b_low + b_high * a_low
      c_high = c >> 32
      c_low = c & 0xFFFFFFFF

      # 31-bit + 31-bit
      res_high = a_high * b_high + c_high
      # 32-bit + 32-bit
      res_low = a_low * b_low
      res_low_high = res_low >> 32
      res_low_low = res_low & 0xFFFFFFFF

      # Overflow
      if res_low_high + c_low >= 0x100000000
        res_high += 1
      end

      res_low = (((res_low_high + c_low) & 0xFFFFFFFF) << 32) | res_low_low

      (((res_high.to_i128 << 64) | res_low) % mod).to_i64
    end

    @[AlwaysInline]
    def self.mul_mod(a, b, mod)
      typeof(mod).new(a.to_i64 * b % mod)
    end

    # Implements atcoder::crt(remainders, modulos).
    def self.crt(remainders, modulos)
      raise ArgumentError.new unless remainders.size == modulos.size

      total_modulo = 1_i64
      answer = 0_i64

      remainders.zip(modulos).each do |(remainder, modulo)|
        gcd, p = extended_gcd(total_modulo, modulo)
        if (remainder - answer) % gcd != 0
          return 0_i64, 0_i64
        end
        tmp = (remainder - answer) // gcd * p % (modulo // gcd)
        answer += total_modulo * tmp
        total_modulo *= modulo // gcd
      end

      return answer % total_modulo, total_modulo
    end

    # Implements atcoder::floor_sum(n, m, a, b).
    def self.floor_sum(n, m, a, b)
      n, m, a, b = n.to_i64, m.to_i64, a.to_i64, b.to_i64
      res = 0_i64

      if a < 0
        a2 = a % m
        res -= n * (n - 1) // 2 * ((a2 - a) // m)
        a = a2
      end

      if b < 0
        b2 = b % m
        res -= n * ((b2 - b) // m)
        b = b2
      end

      res + floor_sum_unsigned(n, m, a, b)
    end

    private def self.floor_sum_unsigned(n, m, a, b)
      res = 0_i64

      loop do
        if a >= m
          res += n * (n - 1) // 2 * (a // m)
          a = a % m
        end

        if b >= m
          res += n * (b // m)
          b = b % m
        end

        y_max = a * n + b
        break if y_max < m

        n = y_max // m
        b = y_max % m
        m, a = a, m
      end

      res
    end
  end
end

module AtCoder
  # Implements [Ruby's Prime library](https://ruby-doc.com/stdlib/libdoc/prime/rdoc/Prime.html).
  #
  # ```
  # AtCoder::Prime.first(7) # => [2, 3, 5, 7, 11, 13, 17]
  # ```
  module Prime
    extend self
    include Enumerable(Int64)

    @@primes = [
      2_i64, 3_i64, 5_i64, 7_i64, 11_i64, 13_i64, 17_i64, 19_i64,
      23_i64, 29_i64, 31_i64, 37_i64, 41_i64, 43_i64, 47_i64,
      53_i64, 59_i64, 61_i64, 67_i64, 71_i64, 73_i64, 79_i64,
      83_i64, 89_i64, 97_i64, 101_i64,
    ]

    def each
      index = 0
      loop do
        yield get_nth_prime(index)
        index += 1
      end
    end

    def prime_division(value : Int)
      raise DivisionByZeroError.new if value == 0

      int = typeof(value)

      factors = [] of Tuple(typeof(value), typeof(value))

      if value < 0
        value = value.abs
        factors << {int.new(-1), int.new(1)}
      end

      until prime?(value) || value == 1
        factor = value
        until prime?(factor)
          factor = find_factor(factor)
        end
        count = 0
        while value % factor == 0
          value //= factor
          count += 1
        end
        factors << {int.new(factor), int.new(count)}
      end

      if value > 1
        factors << {value, int.new(1)}
      end

      factors.sort_by! { |(factor, _)| factor }
    end

    private def find_factor(n : Int)
      # Factor of 4 cannot be discovered by Pollard's Rho with f(x) = x^x+1
      if n == 4
        typeof(n).new(2)
      else
        pollard_rho(n).not_nil!
      end
    end

    # Get single factor by Pollard's Rho Algorithm
    private def pollard_rho(n : Int)
      typeof(n).new(1).upto(n) do |i|
        x = i
        y = pollard_random_f(x, n)

        loop do
          x = pollard_random_f(x, n)
          y = pollard_random_f(pollard_random_f(y, n), n)
          gcd = (x - y).gcd(n)

          if gcd == n
            break
          end

          if gcd != 1
            return gcd
          end
        end
      end
    end

    private def pollard_random_f(n : Int, mod : Int)
      (AtCoder::Math.mul_mod(n, n, mod) + 1) % mod
    end

    private def extract_prime_division_base(prime_divisions_class : Array({T, T}).class) forall T
      T
    end

    def int_from_prime_division(prime_divisions : Array({Int, Int}))
      int_class = extract_prime_division_base(prime_divisions.class)
      prime_divisions.reduce(int_class.new(1)) { |i, (factor, exponent)| i * factor ** exponent }
    end

    def prime?(value : Int)
      # Obvious patterns
      return false if value < 2
      return true if value <= 3
      return false if value.even?
      return true if value < 9

      if value < 0xffff
        return false unless typeof(value).new(30).gcd(value % 30) == 1

        7.step(by: 30, to: value) do |base|
          break if base * base > value

          if {0, 4, 6, 10, 12, 16, 22, 24}.any? { |i| value % (base + i) == 0 }
            return false
          end
        end

        return true
      end

      miller_rabin(value.to_i64)
    end

    private def miller_rabin(value)
      d = value - 1
      s = 0_i64
      until d.odd?
        d >>= 1
        s += 1
      end

      miller_rabin_bases(value).each do |base|
        next if base == value

        x = AtCoder::Math.pow_mod(base.to_i64, d, value)
        next if x == 1 || x == value - 1

        is_composite = s.times.all? do
          x = AtCoder::Math.mul_mod(x, x, value)
          x != value - 1
        end

        return false if is_composite
      end

      true
    end

    # We can reduce time complexity of Miller-Rabin tests by testing against
    # predefined bases which is enough to test against primarity in the given range.
    # https://en.wikipedia.org/wiki/Miller%E2%80%93Rabin_primality_test
    # ameba:disable Metrics/CyclomaticComplexity
    private def miller_rabin_bases(value)
      case
      when value < 1_373_653_i64
        [2, 3]
      when value < 9_080_191_i64
        [31, 73]
      when value < 25_326_001_i64
        [2, 3, 5]
      when value < 3_215_031_751_i64
        [2, 3, 5, 7]
      when value < 4_759_123_141_i64
        [2, 7, 61]
      when value < 1_122_004_669_633_i64
        [2, 13, 23, 1662803]
      when value < 2_152_302_898_747_i64
        [2, 3, 5, 7, 11]
      when value < 3_474_749_660_383_i64
        [2, 3, 5, 7, 11, 13]
      when value < 341_550_071_728_321_i64
        [2, 3, 5, 7, 11, 13, 17]
      when value < 3_825_123_056_546_413_051_i64
        [2, 3, 5, 7, 11, 13, 17, 19, 23]
      else
        [2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37]
      end
    end

    private def get_nth_prime(n)
      while @@primes.size <= n
        generate_primes
      end

      @@primes[n]
    end

    # Doubles the size of the cached prime array and performs the
    # Sieve of Eratosthenes on it.
    private def generate_primes
      new_primes_size = @@primes.size < 1_000_000 ? @@primes.size : 1_000_000
      new_primes = Array(Int64).new(new_primes_size) { |i| @@primes.last + (i + 1) * 2 }
      new_primes_max = new_primes.last

      @@primes.each do |prime|
        next if prime == 2
        break if prime * prime > new_primes_max

        # Here I use the technique of the Sieve of Sundaram. We can
        # only test against the odd multiple of the given prime.
        # min_composite is the minimum number that is greater than
        # the last confirmed prime, and is an odd multiple of
        # the given prime.
        min_multiple = ((@@primes.last // prime + 1) // 2 * 2 + 1) * prime
        min_multiple.step(by: prime * 2, to: new_primes_max) do |multiple|
          index = new_primes_size - (new_primes_max - multiple) // 2 - 1
          new_primes[index] = 0_i64
        end
      end

      @@primes.concat(new_primes.reject(0_i64))
    end

    private struct EachDivisor(T)
      include Enumerable(T)

      def initialize(@exponential_factors : Array(Array(T)))
      end

      def each
        Array.each_product(@exponential_factors) do |factors|
          yield factors.reduce { |a, b| a * b }
        end
      end
    end

    # Returns an enumerator that iterates through the all positive divisors of
    # the given number. **The order is not guaranteed.**
    # Not in the original Ruby's Prime library.
    #
    # ```
    # AtCoder::Prime.each_divisor(20) do |n|
    #   puts n
    # end # => Puts 1, 2, 4, 5, 10, and 20
    #
    # AtCoder::Prime.each_divisor(10).map { |n| 1.0 / n }.to_a # => [1.0, 0.5, 0.2, 0.1]
    # ```
    def each_divisor(value : Int)
      raise ArgumentError.new unless value > 0

      factors = prime_division(value)

      if value == 1
        exponential_factors = [[value]]
      else
        exponential_factors = factors.map do |(factor, count)|
          cnt = typeof(value).zero + 1
          Array(typeof(value)).new(count + 1) do |i|
            cnt_copy = cnt
            if i < count
              cnt *= factor
            end
            cnt_copy
          end
        end
      end

      EachDivisor(typeof(value)).new(exponential_factors)
    end

    # :ditto:
    def each_divisor(value : T, &block : T ->)
      each_divisor(value).each(&block)
    end
  end
end

struct Int
  def prime?
    AtCoder::Prime.prime?(self)
  end
end

n = read_line.to_i
a = read_line.split.map(&.to_i)
x = a.map { |x|
  AtCoder::Prime.prime_division(x).sum(&.[1])
}.reduce(0) { |acc, x|
  acc ^ x
}
puts x > 0 ? "white" : "black"
yukicoder

結果

テストケース

ソースコード
