/**
* get all k-1 candidate sequences
*
* @param seq - parent sequence
* @return a list of sequences
*/
public static ArrayList<ItemSet> getsubSequences(Sequence seq) {
int n = seq.getAllItems().size();
int[] masks = new int[n];
ArrayList<ItemSet> subSequences = new ArrayList<ItemSet>();
for (int i = 0; i < n; i++) {
masks[i] = (1 << i);
}
for (int i = 0; i < (1 << n); i++) {
ArrayList<Integer> newList = new ArrayList<Integer>();
for (int j = 0; j < n; j++) {
if ((masks[j] & i) != 0) {
newList.add(seq.getAllItems().get(j));
}
}
if (newList.size() == n - 1) {
ItemSet is = new ItemSet();
is.setItems(newList);
subSequences.add(is);
}
}
return subSequences;
}
/**
* returns all sequences of a specific size
*
* @param frequentSequences - list of sequences
* @param size specified size of the sequences
* @return list of sequences
*/
public static ArrayList<Sequence> getOfSize(ArrayList<Sequence> frequentSequences, int size) {
ArrayList<Sequence> setOfSize = new ArrayList<Sequence>();
for (Sequence seq : frequentSequences) {
if (seq.getAllItems().size() == size) {
setOfSize.add(seq);
}
}
return setOfSize;
}
