project-euler/Sidef/191 Prize Strings.sf

#!/usr/bin/ruby

# Daniel "Trizen" Șuteu
# Date: 19 October 2017
# https://github.com/trizen

# Runtime: 0.143s

# https://projecteuler.net/problem=191

func p_191(Number days) {
    func (len=0, hasL=false, hasA1=false, hasA2=false) is cached {

        var count = ((len == days) ? 1 : 0)

        if (len < days) {

            if (!hasA1 || !hasA2) {
                count += __FUNC__(len + 1, hasL, hasA2, true)
            }

            count += __FUNC__(len + 1, hasL, hasA2, false)

            if (!hasL) {
                count += __FUNC__(len + 1, true, hasA2, false)
            }
        }

        return count
    }()
}

say p_191(30)