private static void addToQueue(
LinkedList<IntNaryTree> queue, IntBinaryTree child, Alphabet<String> ntAlphabet) {
if (child == null) {
return;
}
String symbolStr = child.getSymbolStr();
if (GrammarConstants.isBinarized(symbolStr)) {
addToQueue(queue, child.leftChild, ntAlphabet);
addToQueue(queue, child.rightChild, ntAlphabet);
} else {
queue.add(child.collapseToNary(ntAlphabet));
}
}
public IntNaryTree collapseToNary(Alphabet<String> ntAlphabet) {
Alphabet<String> alphabet = isLexical ? this.alphabet : ntAlphabet;
// Reset the symbol id according to the new alphabet.
int symbol = alphabet.lookupIndex(getSymbolLabel());
ArrayList<IntNaryTree> children = null;
if (!isLeaf()) {
assert (leftChild != null);
LinkedList<IntNaryTree> queue = new LinkedList<IntNaryTree>();
addToQueue(queue, leftChild, ntAlphabet);
addToQueue(queue, rightChild, ntAlphabet);
children = new ArrayList<IntNaryTree>(queue);
}
return new IntNaryTree(symbol, start, end, children, isLexical, alphabet);
}