COP-3530 Data Structures and Algorithms Midterm I 1

Material Chapters 1-11 of the textbook. PowerPoint Lectures 1-18. Topics not covered: Section 6.5: Binsort, Radix sort, Convex Hull. Section 7.7: Union-find problem. Section 10.5.3: Image-component Labeling. Section 10.5.4: Machine Shop Simulation. 2

The Exam See Textbook web site for sample questions, and their solutions. NO true/false, multiple choice questions. Questions intended to show expertise (not just basic understanding) developed by conscientious work on homeworks, and studying the material. You need to know not only what is, but WHY. 3

Exam (continued) Emphasis is on DESIGN (choice among alternatives). Questions can and DO require interpretation. Closed book exam, but excessive memorization is not required. “Cheat-sheet” not allowed, but preparing one is a good way to study. Emphasis NOT on C++ syntax. 4

Exam (continued) 50 minutes. Expect 3-5 problems, 12-15 minutes each. NO “do any 3 out of 4” . Expect to be pressed for time (somewhat). Standard scale of 0-100 (maybe 105) points. 5

Question Types Type 0: Basic Understanding, or “regurgitation” questions. Type 1: “Crank the handle” questions. Type 2: “Coding” questions. Type 3: “Synthesis” questions. 6

Type 0 Questions Basic Understanding questions: Example: “What is the difference between a stack and a queue ?” “Fact regurgitation” questions: Example: “The two principal implementations of a LinearList are ‘___________’ and ‘___________’ ” 7

Type 1 Questions “Crank the handle” questions: An algorithm is described or mentioned, involving a data structure you’re familiar with. Some initial data are depicted. You show the effect of the algorithm upon the data structure. Examples: rat in a maze, railroad cars, insert/delete from hash-coded table, encode/decode message with LZW compression. 8

Type 2 Questions Coding questions: Set up a scenario: a data structure you should be familiar with. Formulate a problem: a new method, a new version of an old method, a change in the instance variables, a change in required asymptotic behavior You write the necessary code. You analyze the complexity of the result. Example: sparse matrices, see sample tests. 9

Type 3 Questions “Synthesis” Questions. Designed to take it “one step further”. A scenario for a NEW data structure, or a new implementation, or a new application, is presented. You are asked to (partially or totally) design the data structure, or the application, or the implementation. Example: invert a sparse matrix. 10

Distribution of Question Types Type 0: Regurgitation: 0%. Type 1: Crank the handle: 50-60%. Type 2: Coding: 30-40%. Type 3: Synthesis 10-20%. Note: A question can be of multiple types. 11

Advice. Read questions CAREFULLY. Consider your assumptions carefully. Don’t rush to write down the first way you think of doing it. There may be a better one. Don’t get bogged down on syntax. Make sure your answer fits the question. 12