Suppose a binary search tree with 1000 distinct elements is also a complete binary tree. The tree is stored using the array representation of binary heap trees. Assuming that the array indices start with 0, the 3^rd largest element of the tree is stored at index ___________.

Consider a complete binary tree with 7 nodes. Let A denote the set of first 3 elements obtained by performing Breadth-First Search (BFS) starting from the root. Let B denote the set of first 3 elements obtained by performing Depth-First Search (DFS) starting from the root.

The value of |A - B| is _______

Consider the following statements.

S₁ : The sequence of procedure calls corresponds to a preorder traversal of the activation tree.

S₂ : The sequence of procedure returns corresponds to a postorder traversal of the activation tree.

Which one of the following options is correct?