func Filter(d DictSlice, bag bag.Bag) DictSlice {
result := make(DictSlice, 0)
for _, entry := range d {
_, ok := bag.Subtract(entry.Bag)
// seems a shame to throw away the difference.
if ok {
result = append(result, entry)
}
}
return result
}
func Anagrams(d DictSlice, bag bag.Bag) [][]string {
d = Filter(d, bag)
result := make([][]string, 0)
for index, entry := range d {
// try to subtract our bag from this entry's bag; save result in "smaller bag".
smaller_bag, ok := bag.Subtract(entry.Bag)
switch {
// if we cannot, just skip this entry.
case !ok:
break
// if smaller bag is empty, "listify" this entry's words,
// and append that list to the result.
case smaller_bag.Empty():
for _, w := range entry.Words {
new_list := make([]string, 1)
new_list[0] = w
result = append(result, new_list)
}
// otherwise
default:
// recursively call ourselves with the smaller dict and
// the smaller bag
from_recursive_call := Anagrams(d[index:], smaller_bag)
// make a "cross-product" of this entry's words with the
// results of that recursive call.
for _, more := range combine(entry.Words, from_recursive_call) {
result = append(result, more)
}
}
}
return result
}