The   shortest common supersequence   is a problem closely related to the   longest common subsequence,   which you can use as an external function for this task.



Task

Given two strings 



u


{\displaystyle u}

 and 



v


{\displaystyle v}

, find the shortest possible sequence 



s


{\displaystyle s}

, which is the shortest common super-sequence of 



u


{\displaystyle u}

 and 



v


{\displaystyle v}

 where both 



u


{\displaystyle u}

 and 



v


{\displaystyle v}

 are a subsequence of 



s


{\displaystyle s}

. Defined as such, 



s


{\displaystyle s}

 is not necessarily unique.

Demonstrate this by printing 



s


{\displaystyle s}

 where 



u
=


{\displaystyle u=}

“abcbdab” and 



v
=


{\displaystyle v=}

“bdcaba”.



Also see

 Wikipedia: shortest common supersequence 


func scs(u, v) {
    var ls = lcs(u, v).chars
    var pat = Regex('(.*)'+ls.join('(.*)')+'(.*)')
    u.scan!(pat)
    v.scan!(pat)
    var ss = (u.shift + v.shift)
    ls.each { |c| ss += (c + u.shift + v.shift) }
    return ss
}
 
say scs("abcbdab", "bdcaba")