Data Structures & Algorithm An alysis in JAVA (CMPE250)

Data Structures & AlgorithmAnalysis in JAVA(CMPE250) Fatih Alagöz alagoz@boun.edu.tr Office: ETA42 Ext.6652 www.cmpe.boun.edu.tr/alagoz

3, 2, and take off  Data Structures and Algorithm Analysis in JAVA Data Structure: methods of organizing large amounts of data Eg. In the VULCAN Project, Kandilli Obs.&Res.Center will receive about 2GB/day to predict earthquakes in Turkey!!! Storage, processing, etc.

Algorithm: step-by-step procedure for solving a problem in a finite amount of time. i.e. Do NOT start coding be4 analyzing the algorithm!!! Eg. The running time of ARAM algorithm was only 26 hrs, it could have taken approximately 675000 yrs  Could you have done any better? Yes... Data Structures and Algorithm Analysis in JAVA-2

JAVA: relatively new language and superior (?) to C++: With being user-friendly, safe, portable, etc At the expense of: Limited I/O support. JAVA >> convert >> C++ (easy) C++ >> convert >>JAVA !!! should locate hidden traps with I/O classes first. Course Content is Language Independent but Use JAVA for implementations Data Structures and Algorithm Analysis in JAVA-3

CATALOG DATA: Data Structures &Algorithms (3+0+2) 4 Complexity, Hashing, Heap Structures, Advanced Sorting, Search Structures, Graphs, Parallel Algorithms, File organization. Prerequisite: CmpE 160 Course Syllabus (Review)

Textbook: M. A. Weiss, Data Structures and algorithm and Algorithm Analysis in Java, Addison Wesley, 2nd edition 2007. (or 99 edition). References: Drozdek Adam, Data Structures and Algorithms in Java, Brooks Cole, 2001. M. T. Goodrich and R. Tamassia, Data Structures and Algorithms in Java(3/e), Wiley and Sons, 2004. Course Syllabus (Review)

Teaching Team: Instructor:Fatih Alagoz TAs: Hande Ozgur Alemdar www.cmpe.boun.edu.tr GOAL: To learn the specifications, usage, implementation & analysis of advanced data structures & algorithms using JAVA. Prerequisites by topic Programming in C, C++ Fluency with the implementation of basic data structures Some background in discrete math Course Syllabus (Review)

ABET category content as estimated by faculty member who prepared this course description Engineering science: 1.5 credits or 37.5 % Engineering design : 2.5 credits or 63.5 % Grading Policy (Tentative): Midterm exam 1 17.5% Midterm exam 2 17.5% Projects + Pop Quizzes + HWs 25% Final exam 40% Note: Midterm exam date will be announced a week prior to the exam! Course Syllabus (Review)

Series Summations: • Logarithms and Exponents logb(xy) = logbx + logby a(b+c) = aba c logb (x/y) = logbx – logby abc = (ab)c logbxa = alogbx ab /ac = a(b-c) logba = logxa/logxb b = a logab bc = a c*logab • Proof techniques: induction, counterexample, and contradiction Math Review

Programming with Recursion

The Recursion Pattern • Recursion: when a method calls itself • Classic example--the factorial function: • n! = 1· 2· 3· ··· · (n-1)· n • Recursive definition: • As a Java method: // recursive factorial function public static int recursiveFactorial(int n) { if (n == 0) return 1; // basis case else return n * recursiveFactorial(n- 1); // recursive case }

Content of a Recursive Method • Base case(s). • Values of the input variables for which we perform no recursive calls are called base cases (there should be at least one base case). • Every possible chain of recursive calls must eventually reach a base case. • Recursive calls. • Calls to the current method. • Each recursive call should be defined so that it makes progress towards a base case.

return 4 * 6 = 24 final answer call recursiveFactorial ( 4 ) return 3 * 2 = 6 call recursiveFactorial ( 3 ) return 2 * 1 = 2 call recursiveFactorial ( 2 ) return 1 * 1 = 1 call recursiveFactorial ( 1 ) return 1 call recursiveFactorial ( 0 ) Visualizing Recursion Example recursion trace: • Recursion trace • A box for each recursive call • An arrow from each caller to callee • An arrow from each callee to caller showing return value

Example – English Rulers(*) • Define a recursive way to print the ticks and numbers like an English ruler:

A Recursive Method for Drawing Ticks on an English Ruler(*) // draw a tick with no label public static void drawOneTick(int tickLength) { drawOneTick(tickLength, - 1); } // draw one tick public static void drawOneTick(int tickLength, int tickLabel) { for (int i = 0; i< tickLength; i++) System.out.print("-"); if (tickLabel >= 0) System.out.print(" " + tickLabel); System.out.print("\n"); } public static void drawTicks(int tickLength) { // draw ticks of given length if (tickLength > 0) { // stop when length drops to 0 drawTicks(tickLength- 1); // recursively draw left ticks drawOneTick(tickLength); // draw center tick drawTicks(tickLength- 1); // recursively draw right ticks } } public static void drawRuler(int nInches, int majorLength) { // draw ruler drawOneTick(majorLength, 0); // draw tick 0 and its label for (int i = 1; i <= nInches; i++) { drawTicks(majorLength- 1); // draw ticks for this inch drawOneTick(majorLength, i); // draw tick i and its label } }

drawTicks ( 3 ) Output drawTicks ( 2 ) drawTicks ( 1 ) drawTicks ( 0 ) drawOneTick ( 1 ) drawTicks ( 0 ) drawOneTick ( 2 ) drawTicks ( 1 ) drawTicks ( 0 ) drawOneTick ( 1 ) drawTicks ( 0 ) drawOneTick ( 3 ) drawTicks ( 2 ) ( previous pattern repeats ) Visualizing the DrawTicks Method(*) • An interval with a central tick length L >1 is composed of the following: • an interval with a central tick length L-1, • a single tick of length L, • an interval with a central tick length L-1.

HWLA: HomeWorkLikeAssignment • Download the JAVA tutorial from the course website • http://users.cs.fiu.edu/~weiss/dsaajava2/code/ • Visit www.cs.fiu.edu/^weiss for Code Availability • Write your first JAVA code that converts Celcius to Fahrenheit for the range [-50 50]. Introduce exception for out of the range inputs. • Solve exercises

Data Structures & Algorithm An alysis in JAVA (CMPE250)