sclass SuffixTree_managed implements IManagedObject, AutoCloseable {

  replace Addr with int.

  new ManagedIntObjects_v1 mem;

  Node root;

  CharSequence fullText;

  int nodeCount;

  Cl<AutoCloseable> dependentCloseables;

  Comparator<Node> childComparator = (a, b) -> a.firstCharOrMinus1(this)-b.firstCharOrMinus1(this);

  class Node extends AbstractManagedObject {

    // children is a pointer to an int "array" (length field + ints)

    final static int ofs_from = 0, ofs_to = 1, ofs_children = 2;

    final static int objectSize = ofs_children+1;

    *(Addr addr) { super(addr); }

    // create new object

    *() {

      addr = mem.alloc(objectSize);

    }

    // create new object

    *(int from, int to) {

      this();

      from(from);

      to(to);

    }

    // create new object

    *(Substring s) {

      this(s.startIndex(), s.endIndex());

    }

    // fields & GC handling

    int from() { ret mem.get(addr+ofs_from); }

    int to() { ret mem.get(addr+ofs_to); }

    Addr children_ptr() { ret mem.get(addr+ofs_children); }

    L<Node> children() {

      ret convertListElementsBothWays(

        n -> new Node(n),

        n -> n.addr,

        mem.pointerArray(children_ptr()));

    }

    void from(int from) { mem.set(addr+ofs_from, from); }

    void to(int to) { mem.set(addr+ofs_to, to); }

    void children(Addr addr) { mem.set(this.addr+ofs_children, addr); }

    public void scanForCollection(IManagedObjectCollector gc) {

      gc.noteObject(addr, objectSize, this == root ? newAddr -> { addr = newAddr; } : null);

      gc.notePointer(addr+ofs_children);

      gc.notePointerArray(children_ptr());

      for (Node n : children())

        n.scanForCollection(gc);

    }

    // other methods

    Substring text(SuffixTree_managed tree) { ret Substring(tree.fullText, from(), to()); }

    int lText() { ret to()-from(); }

    bool isTerminal(SuffixTree_managed tree) { ret to() == l(tree.fullText); }

    void addChild(SuffixTree_managed tree, Node n) {

      Addr oldChildren = children_ptr();

      int i = l(children());

      //print(children_ptr := children_ptr() + ", l=" + l(children()));

      children(mem.resizePointerArray(oldChildren, i+1);

      //print(children_ptr := children_ptr() + ", l=" + l(children()));

      mem.freePointerArray(oldChildren);

      children().set(i, n);

      sortInPlace(children(), tree.childComparator);

    }

    public int firstCharOrMinus1(SuffixTree_managed tree) {

      ret charToIntOrMinus1(text(tree));

    }

    Node getChild(SuffixTree_managed tree, int c) {

      L<Node> children = children();

      int i = generalizedBinarySearch2(children, n -> cmp(n.firstCharOrMinus1(tree), c));

      ret i >= 0 ? children.get(i) : null;

    }

    toString { ret "Node@" + addr + ", " + from() + "/" + lText() + ". " + nChildren(children()); }

  }

  *() {}

  *(S *fullText) {

    process(fullText);

  }

  // load

  *(IIntMemory mem, int root) {

    this.mem = new ManagedIntObjects_v1_virtual(mem);

    this.root = new Node(root);

  }

  void process(S fullText) {

    this.fullText = fullText;

    root = new Node(0, 0);

    ++nodeCount;

    for i over fullText: {

      addSuffix(Substring(fullText, i));

      if (((i+1) % 1000000) == 0) {

        print((i+1) + " suffixes added (" + nNodes(nodeCount) + ")");

        mem.printStats();

      }

    }

  }

  void addSuffix(Substring s) {

    Node node = root;

    while (!empty(s)) {

      int _n = lCommonPrefix_CharSequence(node.text(SuffixTree_managed.this), s);

      s = s.substring(_n);

      if (_n >= node.lText()) { // node text exhausted

        if (empty(s)) { // pattern also exhausted - done

          //print("Exhausted: " + node.from() + "/" + node.to());

          // add a new termination node

          Node nNew = new Node(s);

          ++nodeCount;

          node.addChild(SuffixTree_managed.this, nNew);

          ret;

        } else {

          Node n = node.getChild(SuffixTree_managed.this, charToIntOrMinus1(s));

          if (n == null) {

            n = new Node(s);

            ++nodeCount;

            node.addChild(SuffixTree_managed.this, n);

            ret;

          } else

            node = n;

        }

      } else { // node text not exhausted

        // split node. first, move all the node's vitals to a new node nOld

        Node nOld = new Node(node.from()+_n, node.to());

        ++nodeCount;

        nOld.children(node.children_ptr());

        node.children(mem.nullPtr());

        node.to(node.from()+_n);

        node.addChild(SuffixTree_managed.this, nOld);

        // now add a new node

        Node nNew = new Node(s);

        ++nodeCount;

        node.addChild(SuffixTree_managed.this, nNew);

        ret;

      }

    }

  }

  public L<Int> indicesOf(S pattern) {

    ret asList(indicesOf_iterator(pattern));

  }

  public ItIt<Int> indicesOf_iterator(S pattern) {

    ret mapI_notNull(allNodesUnder(scanDown(root, pattern)),

      nad -> nad.node.isTerminal(this) ? nad.position() : null);

  }

  srecord NodeAndDepth(Node node, int depth) {

    int position() {

      int position = node.from()-depth;

      //print("from=" + node.from() + ", to=" + node.to() + ", depth=" + depth + ", position=" + position);

      ret position;

    }

    Cl<NodeAndDepth> children() {

      ret lmap wrapChild(node.children());

    }

    NodeAndDepth wrapChild(Node n) {

      ret n == null ? null : new NodeAndDepth(n, depth+node.lText());

    }

    NodeAndDepth getChild(SuffixTree_managed tree, int c) {

      ret wrapChild(node.getChild(tree, c));

    }

  }

  NodeAndDepth scanDown(Node node, S pattern) {

    int lPattern = l(pattern), iPattern = 0;

    NodeAndDepth nad = new(node, 0);

    while true {

      int n = lCommonPrefix_CharSequence(nad.node.text(this), Substring(pattern, iPattern));

      iPattern += n;

      if (iPattern >= lPattern) break; // pattern exhausted - done

      if (n < nad.node.lText()) null; // mismatch, exit

      NodeAndDepth child = nad.getChild(SuffixTree_managed.this, charAtAsIntOrMinus1(pattern, iPattern));

      if (child != null) continue with nad = child;

      null;

    }

    ret nad;

  }

  void printMe() {

    printNode("", "", new NodeAndDepth(root, 0));

  }

  void printNode(S indent, S pre, NodeAndDepth nad) {

    print(indent + pre + quote(shorten(20, nad.node.text(this))) + (!nad.node.isTerminal(this) ? "" : " [" + nad.position() + "]"));

    fOr (NodeAndDepth n : nad.children()) {

      printNode(indent + "  ", "[" + (n.node.lText() == 0 ? "end" : quote(n.node.text(this).charAt(0))) + "] ", n);

    }

  }

  ItIt<NodeAndDepth> allNodes() {

    ret allNodesUnder(new NodeAndDepth(root, 0));

  }

  // includes the node itself

  ItIt<NodeAndDepth> allNodesUnder(NodeAndDepth nad) {

    new L<Iterator<NodeAndDepth>> stack;

    if (nad != null)

      stack.add(iteratorLL(nad));

    ret iteratorFromFunction_if0(() -> {

      while (nempty(stack)) {

        if (!last(stack).hasNext())

          popLast(stack);

        else {

          NodeAndDepth n = last(stack).next();

          stack.add((Iterator) iterator(n.children()));

          ret n;

        }

      }

      null;

    });

  }

  public void scanForCollection(IManagedObjectCollector gc) {

    if (root == null) ret;

    root.scanForCollection(gc);

  }

  public void close() {

    closeAll(dependentCloseables);

  }

}