Question

New to Ruby, and trying to find a 3 digits number “abc”:

for a in 0..9
    for b in 0..9
        for c in 0..9
            if a*a+b*b+c*c == (100*a+10*b+c)/11.0
                puts "#{a}#{b}#{c}"
            end
        end
    end
end

This is too lengthy, is any way to optimize it, or write it in another “ruby” way?

Answer 1

Solution from: Wolfram Alpha 🙂

Here’s another fun solution. Not really faster, just more compact and perhaps more ruby-like if that was what you were looking for:

(0..9).to_a.repeated_permutation(3).select { |a,b,c| 
  a*a+b*b+c*c == (100*a+10*b+c)/11.0 
}
=> [[0, 0, 0], [5, 5, 0], [8, 0, 3]]