Ruby Euler project Non-abundant sums 23 Code

Question

丰数是其固有因数之和大于该数本身的数。欧拉工程的一个问题是:"找出所有不能写成两个富数和的正整数的和。"我应该得到:

12, 18, 20, 24, etc.

代码是:

def check_abundant(x)
  total(x) > x
end
def total (x)
  sum = 1
  (2..Math.sqrt(x)).each do |i|
    sum = sum + x + x/i if x%i == 0 && i != Math.sqrt(x)
  end
  sum
end
def non_abundant_sums
  abundant_arr = []
  s = 0
  (12..28123).each do |x|
    if check_abundant(x)
      abundant_arr << x
    end
    (1..28123).each do |x|
      s = s + x unless abundant_arr.include? (total(x) - x)
    end
    s
  end
  puts non_abundant_sums

当我输出abundant_arr时，我得到

12, 14, 15

Answer 1

这里有一些东西可以让你开始。这需要一些时间来完成。

def proper_divisors(num)
  (1...num).select { |n| num % n == 0 }
end
def abundant?(n)   
  proper_divisors(n).reduce(:+) > n
end 
arr = (12..28123).map { |n| print "." if n % 100 == 0; n if abundant?(n) }.compact
 => [12, 18, 20, 24, 30, 36, 40...]