get primes

1621.rb

raw_list = []
while str = STDIN.gets.chomp
  break if str.empty?
  raw_list.push str.to_i
end

class GetterPrimer
  def initialize
    @primes = [2]
    @max_checked = 2
  end

  def get_primes_size_memorize(number)
    if number <= @max_checked
      @primes.select{|p| p < number}
        .size
    elsif
      count = @max_checked % 2 == 0 ? @max_checked - 1 : @max_checked
      while count < number
        self.is_prime? count
        count += 2
      end
      @max_checked = number - 1

      @primes.size
    end
  end

  def is_prime?(num)
    # 負の数, 0, 1, 偶数は素数でない, 2は素数
    if not num.is_a? Integer
      return false
    elsif num <= 0
      return false
    elsif num == 1
      return false
    elsif num == 2
      return true
    elsif num % 2 == 0
      return false
    elsif num <= @max_checked
      return @primes.include? num
    else
      prime = true
      # 今まで見つけた素数でチェックする
      # 連番じゃないと使えない
      @primes.each{ |p|
        prime = false if num % p == 0
      }

      if prime
        @primes << num
      end

      @max_checked = num
      prime
    end
  end
  protected :is_prime?
end
resolver = GetterPrimer.new
#raw_list.each{ |num| puts resolver.get_primes_size_memorize num.to_i }
require 'benchmark'
raw_list.each{ |num| 
  ans = nil
  time = Benchmark.measure {
    ans = resolver.get_primes_size_memorize num.to_i
  }.total
  puts "#{time}: #{num}, #{ans}"
}