UnambiguousAbbreviation.txt

Given a string, return the shortest "unambiguous abbreviation" of that string.

Assume that your input string is a non-empty string consisting of lowercase letters (a-z) and spaces.

Example:

   UnambiguousAbbreviation("peter piper picked a peck of pickled peppers") = "pet pip picke a pec o pi p"

Initially, the word bank looks like:

B = ("peter", "piper", "picked", "a", "peck", "of", "pickled", "peppers")

To type "peter", you'd need to type "pet" as that's the shortest unambiguous abbreviation. The word bank now looks like:

B = ("piper", "picked", "a", "peck", "of", "pickled", "peppers")

To type "piper", you'd need to type "pip" as that's the shortest unambiguous abbreviation. The word bank now looks like:

B = ("picked", "a", "peck", "of", "pickled", "peppers")

To type "picked", you'd need to type "picke" as that's the shortest unambiguous abbreviation. The word bank now looks like:

B = ("a", "peck", "of", "pickled", "peppers")

To type "a", you'd need to type "a" as that's the shortest unambiguous abbreviation. The word bank now looks like:

B = ("peck", "of", "pickled", "peppers")

To type "peck", you'd need to type "pec" as that's the shortest unambiguous abbreviation. The word bank now looks like:

B = ("of", "pickled", "peppers")

To type "of", you'd need to type "o" as that's the shortest unambiguous abbreviation. The word bank now looks like:

B = ("pickled", "peppers")

To type "pickled", you'd need to type "pi" as that's the shortest unambiguous abbreviation. The word bank now looks like:

B = ("peppers")

To type "peppers", you'd need to type "p" as that's the shortest unambiguous abbreviation. The word bank now looks like:

B = ()

The word bank is now empty, so we're done. The shortest unambiguous abbreviation of the input string is thus:

"pet pip picke a pec o pi p"

Thus, implement a function like:

    def UnambiguousAbbreviation(bank: list[str]) -> str:
        ...

...in the programming language of your choice.

I ended up writing your `unambiguous-abbreviations` sub as a one-liner...

Like so:

sub unambiguous-abbreviations(+w) {
  w.map({ .&{ [\~] .comb }.first({ w.grep(*.begins-with($_)).uniq.elems == 1 }) or $_ })
}

The .&{ [\~] .comb } gets all the prefixes of $_;
The .first({ w.grep(*.begins-with($_)).uniq.elems == 1 }) is the smallest unambiguous prefix (or Nil, in case there isn't one and you need the full word... hence the or $_ part in the end

@massa Awesome! 🤩 I love how versatile Raku is.