Possible optimization?

[gdetari]

In the following function:

private HashSet<string> Edits(string word, int editDistance, HashSet<string> deleteWords)
    {
        editDistance++;
        if (word.Length > 1)
        {
            for (int i = 0; i < word.Length; i++)
            {
                string delete = word.Remove(i, 1);
                if (deleteWords.Add(delete))
                {
                    //recursion, if maximum edit distance not yet reached
                    if (editDistance < maxDictionaryEditDistance) Edits(delete, editDistance, deleteWords);
                }
            }
        }
        return deleteWords;
    }

Would it make sense to only add to calculate and add the words to deleteWords if editDistance < maxDictionaryEditDistance is true? That is quite a difference in loading dictionary performance. It does change the functionality, but isn't that the correct approach not to add the words anyhow?

[wolfgarbe]

I think we already do exactly this. Edits is a recursive method.
Only in the first iteration we unconditionally calculate and add deletes.
That is because we always have maxDictionaryEditDistance>=1.
But the second and following iterations of Edits are done only if editDistance < maxDictionaryEditDistance.

[gdetari]

Yes, what I meant, that when editDistance == maxDictionaryEditDistance, we do add the delete word, but not call the recursion anymore. I was wondering if we need to add the delete word at all at this case, but now that I pondered on it more, I think it is intentional, right? That case should still be included, just not going anymore deeper with the recursion.