6. Let H be a heap storing 15 entries using the vector representation of a complete binary tree (recall that in this representation, the root is stored at index 1 and the left and right children of the node at index i are stored at indices 2i and 2i +1 respectively). What is the sequence of indices of the vector that are visited in a preorder traversal of H? What about an inorder traversal of H? What about a (10 pts.) postorder traversal of H