static WithChoices<LS> greedySplitIntoWordsCI_withChoices(S s, Cl<S> words) {
  TreeSet<S> wordsSet = asCISet(words);
  int i = 0, last = 0;
  new LS out;
  while (i < l(s)) {
    int longest = l(longestPrefixInCISet(substring(s, i), wordsSet));
    for (int j = l(s); j > i; j--)
      if (contains(wordsSet, substring(s, i, j))) {
        S word = prefixesInCISet(, wordsSet);
    if (nempty(word)) {
      addIfNempty(out, substring(s, last, i));
      out.add(substring(s, i, i+l(word));
      last = i = i+l(word);
    } else ++i;
  }
  addIfNempty(out, substring(s, last, i));
  ret out;
}

Began life as a copy of #1028147