project-euler/Sidef/032 Pandigital products.sf

#!/usr/bin/ruby

# Author: Daniel "Trizen" Șuteu
# License: GPLv3
# Website: https://github.com/trizen

# Find the sum of all products whose multiplicand/multiplier/product identity can be written as a 1 through 9 pandigital.

# https://projecteuler.net/problem=32

# Runtime: 4.574s (previously: 7.707s)

func valid_num(n) {
    var digits = n.digits

    return false if (digits.contains(0))
    return false if (digits.uniq.len != n.len)

    return true
}

var a = (range(1, 99)   -> grep(valid_num))
var b = (range(1, 9999) -> grep(valid_num))

var sum = 0
var seen = Hash()

a.each { |x|
    b.each { |y|
        var prod = x*y
        var pd = ("%s%s%s" % (x, y, prod))

        pd.len == 9        || next
        valid_num(prod)    || next
        valid_num(Num(pd)) || next

        next if seen.has(prod)
        seen{prod} = 1

        say "#{x} * #{y} = #{prod}"
        sum += prod
    }
}

say sum