我正在尝试编写一个程序来找到 2 个整数的最大回文乘积，Ruby

Question

到目前为止我使用的代码如下。 已附加注释以帮助理解错误消息旁边包含的错误

回溯（最近一次调用）：4：来自 main.rb:25:in <main>' 3: from main.rb:6:in palindromic' 2：来自 main.rb:6:in each' 1: from main.rb:6:in downto' main.rb:9:in block in palindromic': undefined method product' for main:Object (NoMethodError) 你的意思是？ 进程

def palindromic(largestDigitNum)
  puts largestDigitNum
  decrementer = largestDigitNum
  palindromicProduct = false
  until palindromicProduct == true
    for i in decrementer.downto(largestDigitNum) do
      product = (largestDigitNum * i).to_s
      reversedProduct = product.reverse
      if reversedProduct == product do
        puts product
        palindromicProduct = true
      end
    end
  end
end
end # for some reason it makes me add another end, I am not sure why but it refuses to function otherwise
print "Enter the number of digits you wish to find the palindromic product of: "
num = gets.chomp!.to_i 
largestDigitNum = 0
j = 1
for i in j.upto(num) do
     largestDigitNum +=  9 * (10 ** (i - 1))
end
puts largestDigitNum
palindromic(largestDigitNum)

Answer 1

获取给定数字大小的所有回文数：

def palindromic_numbers number_of_digits
  max = ('9' * number_of_digits).to_i
  min = ('1' + ('0' * (number_of_digits - 1))).to_i
  min.upto(max).each_with_object([]) do |num, arr|
    str = num.to_s
    arr << num if str == str.reverse
  end
end

palindromic_numbers(2) #=> [11, 22, 33, 44, 55, 66, 77, 88, 99]

注意：此函数不考虑零填充数字