Problem Statement

Given   M   as a list of items and another list   N   of items chosen from   M,   create   M'   as a list with the first occurrences of items from   N   sorted to be in one of the set of indices of their original occurrence in   M   but in the order given by their order in   N. That is, items in   N   are taken from   M   without replacement, then the corresponding positions in   M'   are filled by successive items from   N.

The words not in   N   are left in their original positions.

If there are duplications then only the first instances in   M   up to as many as are mentioned in   N   are potentially re-ordered.

Is ordered as:

Show the output, here, for at least the following inputs:

Let's start with the solution:

func dsort(m, n) {
    var h = Hash()
    n.each {|item| h{item} := 0 ++ }
    m.map  {|item| h{item} := 0 -- > 0 ? n.shift : item}
}

<<'EOT'.lines.each { |line|
        the cat sat on the mat  | mat cat
        the cat sat on the mat  | cat mat
        A B C A B C A B C       | C A C A
        A B C A B D A B E       | E A D A
        A B                     | B
        A B                     | B A
        A B B A                 | B A
EOT
        var (a, b) = line.split('|').map{.words}...
        say "#{a.join(' ')} | #{b.join(' ')} -> #{dsort(a.clone, b.clone).join(' ')}"
}