MerkleTree_Constructor.java

  private final List<List<Bytes32>> tree;
  private final List<Bytes32> zeroHashes;
  private final int height;
  private boolean dirty = true;

  public MerkleTree(int height) {
    assert (height > 1);
    this.height = height;
    tree = new ArrayList<List<Bytes32>>();
    for (int i = 0; i <= height; i++) {
      tree.add(new ArrayList<Bytes32>());
    }
    zeroHashes = generateZeroHashes(height);