19. Write an implemenation of the pop() function of an array-based stack: please explain as well

Answer the following 3 questions using the following answer bank: (a) height (b) depth (e) ancestor (c) root (d) internal node(d) external node 15. The 16. The 17. A[n] of a node is the max number of ancestors it has of a node is the max number of descendants it has (on a path) can't have any children 18. What is the average-case run-time to determine the height of a BST? (assume no internal height variable) b. O(log n) c. O(n) d. O(n log n) e. O(n2)