struct Node {
  Sha256 hash;
  int pos;
}

library MerklePath {
  static const int INVALID_NODE = 0;
  static const int LEFT_NODE = 1;
  static const int RIGHT_NODE = 2;
  static function calcMerkleRoot(Sha256 leaf, Node[32] merkleProof, static const int depth) : Sha256 {
    Sha256 root = leaf;
    loop (depth) : i {
        Node node = merkleProof[i];
        if(node.pos != 0) {
          root = node.pos == 1 ? Sha256(hash256(node.hash + root)) : Sha256(hash256(root + node.hash));
        }
      }
    return root;
  }
  static function isCoinbase(Node[32] merkleproof, static const int depth) : bool {
    bool res = true;
    loop (depth) : i {
        Node node = merkleproof[i];
        if(node.pos != 0) {
          res = res && node.pos == 2;
        }
      }
    return res;
  }
}