static private string subtract_strings(string minuend, string subtrahend)
{
Bag m = new Bag(minuend);
Bag s = new Bag(subtrahend);
Bag diff = m.subtract(s);
if (diff == null)
{
return(null);
}
return(diff.AsString());
}
// return a list that is like dictionary, but which contains only those items which can be made from the letters in bag.
private static List <BagAnagrams> Prune(Bag bag, List <BagAnagrams> dictionary, done_pruning done_pruning_callback, uint recursion_level)
{
List <BagAnagrams> rv = new List <BagAnagrams>();
foreach (BagAnagrams pair in dictionary)
{
Bag this_bag = pair.b;
if (bag.subtract(this_bag) != null)
{
rv.Add(pair);
}
}
done_pruning_callback(recursion_level, rv);
return(rv);
}
public static anagrams anagrams(Bag bag,
List <BagAnagrams> dictionary,
uint recursion_level,
bottom_of_main_loop bottom,
done_pruning done_pruning_callback,
found_anagram success_callback)
{
anagrams rv = new anagrams();
List <BagAnagrams> pruned = Prune(bag,
dictionary,
done_pruning_callback,
recursion_level);
int pruned_initial_size = pruned.Count;
while (pruned.Count > 0)
{
BagAnagrams entry = pruned[0];
Bag this_bag = entry.b;
Bag diff = bag.subtract(this_bag);
if (diff != null)
{
if (diff.empty())
{
foreach (string w in entry.words)
{
strings loner = new strings();
loner.Add(w);
rv.Add(loner);
if (recursion_level == 0)
{
success_callback(loner);
}
}
}
else
{
anagrams from_smaller = anagrams(diff, pruned, recursion_level + 1,
bottom,
done_pruning_callback,
success_callback);
anagrams combined = Combine(entry.words, from_smaller);
foreach (strings an in combined)
{
rv.Add(an);
if (recursion_level == 0)
{
success_callback(an);
}
}
}
}
pruned.RemoveAt(0);
if (recursion_level == 0)
{
bottom();
}
Application.DoEvents();
}
return(rv);
}