Pandigital Squares

# pandigital squares drill

const digits = ['0', '1', '2', '3', '4', '5', '6', '7', '8', '9'];

function is_pandigital(n::Integer)::Bool
    n_string = string(n);
    if length(n_string) != 10; return false; end

    for digit in digits
        if !contains(n_string, digit); return false; end
    end

    true
end

function main()
    a = floor(Int64, sqrt(1000000000)); # no point testing numbers less than this one
    b = floor(Int64, sqrt(9999999999)); # no point testing numbers larger than this one

    for i = a:b
        n = i^2;

    if (n % 3 == 0) && (n % 10 != 0) # expediting process by mitigating search space...
            is_pandigital(n) && println(n)
    end
    end
end