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| 1 | +%% |
| 2 | +%% kit-prog-tutorial |
| 3 | +%% |
| 4 | +%% Slides for my Java programming tutorial at KIT using LaTeX beamer. |
| 5 | +%% |
| 6 | +%% Copyright (c) 2015-2016 YouniS Bensalah <[email protected]> |
| 7 | +%% |
| 8 | +%% This work is released to the public domain. |
| 9 | +%% For the full copyright and license information, please view the LICENSE file. |
| 10 | +%% |
| 11 | + |
| 12 | +\documentclass[18pt]{beamer} |
| 13 | + |
| 14 | +\usepackage{templates/beamerthemekit} |
| 15 | + |
| 16 | +\usepackage[utf8]{inputenc} |
| 17 | +\usepackage{hyperref} |
| 18 | +\usepackage{listings} |
| 19 | +\usepackage{xcolor} |
| 20 | +\usepackage{colortbl} |
| 21 | +\usepackage{array} |
| 22 | +\usepackage{amsmath} |
| 23 | +\usepackage{amssymb} |
| 24 | +\usepackage{mathrsfs} |
| 25 | +\usepackage{eurosym} |
| 26 | + |
| 27 | +\titleimage{road} |
| 28 | + |
| 29 | +\definecolor{lime}{HTML}{8FFF53} |
| 30 | + |
| 31 | +\newcommand{\tagline}{Recursion \& Java API} |
| 32 | + |
| 33 | +\newcommand{\quotes}[1]{``#1''} |
| 34 | + |
| 35 | +\title[Programmieren\hspace{2.5pt}--\hspace{2.5pt}\tagline]{\tagline} |
| 36 | +\subtitle{Programmieren~\textbar~Tutorium 32} |
| 37 | + |
| 38 | +\author{YouniS Bensalah} |
| 39 | +\date{23. Januar 2017} |
| 40 | + |
| 41 | +\institute{Chair for Software Design and Quality} |
| 42 | + |
| 43 | +\usepackage[citestyle=authoryear,bibstyle=numeric,hyperref,backend=biber]{biblatex} |
| 44 | +\addbibresource{templates/example.bib} |
| 45 | +\bibhang1em |
| 46 | + |
| 47 | +\begin{document} |
| 48 | + |
| 49 | +% remove annoying figure prefix in caption |
| 50 | +\setbeamertemplate{caption}{\raggedright\insertcaption\par} |
| 51 | + |
| 52 | +\selectlanguage{english} |
| 53 | + |
| 54 | +\begin{frame} |
| 55 | + \titlepage |
| 56 | +\end{frame} |
| 57 | + |
| 58 | +% \begin{frame}{Heute} |
| 59 | +% \tableofcontents |
| 60 | +% \end{frame} |
| 61 | + |
| 62 | +\begin{frame}{Divide and Conquer} |
| 63 | + \begin{itemize} |
| 64 | + \item \quotes{Teile und herrsche} |
| 65 | + \item Wichtiger Ansatz in der Algorithmik |
| 66 | + \vspace{.2in} |
| 67 | + \begin{enumerate} |
| 68 | + \item Teile Problem so lange in kleinere Teilprobleme, bis diese einfach lösbar sind |
| 69 | + \item Löse die einzelnen Teilprobleme |
| 70 | + \item Füge Teillösungen zu Lösung des Gesamtproblems zusammen |
| 71 | + \end{enumerate} |
| 72 | + \end{itemize} |
| 73 | +\end{frame} |
| 74 | + |
| 75 | +\begin{frame}{Rekursion} |
| 76 | + \begin{itemize} |
| 77 | + \item \textbf{Prinzip der Rekursion} |
| 78 | + \begin{itemize} |
| 79 | + \item Funktion kann sich selbst aufrufen |
| 80 | + \item Führe gleiches Berechnungsmuster immer wieder mit kleineren Eingabedaten aus, bis Problem trivial ist |
| 81 | + \end{itemize} |
| 82 | + \pause |
| 83 | + \vspace{.2in} |
| 84 | + \item Rekursion ist Form von \textit{Divide and Conquer} |
| 85 | + \end{itemize} |
| 86 | +\end{frame} |
| 87 | + |
| 88 | +\begin{frame}{Rekursion} |
| 89 | + Siehe \quotes{Rekursion}. |
| 90 | +\end{frame} |
| 91 | + |
| 92 | +\begin{frame}{Rekursion: Fakultät} |
| 93 | + \begin{exampleblock}{} |
| 94 | + \begin{itemize} |
| 95 | + \item Berechnung der Fakultät einer (nicht negativen, ganzen) Zahl:\\ |
| 96 | + \vspace{.2in} |
| 97 | + $ |
| 98 | + n! = \prod\limits_{i=1}^{n} = |
| 99 | + \begin{cases} |
| 100 | + n \cdot (n-1)! & \text{if\qquad} x > 0 \\ |
| 101 | + 0 & \text{if\qquad} x = 0 |
| 102 | + \end{cases} |
| 103 | + $ |
| 104 | + \end{itemize} |
| 105 | + \end{exampleblock} |
| 106 | +\end{frame} |
| 107 | + |
| 108 | +\begin{frame}[fragile]{Rekursion: Fakultät} |
| 109 | + \begin{exampleblock}{} |
| 110 | + \begin{lstlisting}[language=Java,basicstyle=\scriptsize] |
| 111 | +int factorial(int n) { |
| 112 | + if (n > 0) { |
| 113 | + return n * factorial(n - 1); |
| 114 | + } else { |
| 115 | + return 1; |
| 116 | + } |
| 117 | +} |
| 118 | + \end{lstlisting} |
| 119 | + |
| 120 | + \end{exampleblock} |
| 121 | + |
| 122 | +\end{frame} |
| 123 | + |
| 124 | +\begin{frame}[fragile]{Rekursion: Ackermannfunktion} |
| 125 | + \begin{exampleblock}{} |
| 126 | + $ |
| 127 | + \mathscr{A}(m, n) := |
| 128 | + \begin{cases} |
| 129 | + n+1 & \text{if\quad} m = 0\\ |
| 130 | + \mathscr{A}(m-1, 1) & \text{if\quad} m > 0 \text{\,and\,} n = 0\\ |
| 131 | + \mathscr{A}(m-1, \mathscr{A}(m, n-1)) & \text{if\quad} m > 0 \text{\,and\,} n > 0 |
| 132 | + \end{cases} |
| 133 | + $ |
| 134 | + \end{exampleblock} |
| 135 | + \pause |
| 136 | + \begin{itemize} |
| 137 | + \item $\mathscr{A}(1, 1) = 3$ |
| 138 | + \item $\mathscr{A}(1, 2) = 4$ |
| 139 | + \item $\mathscr{A}(2, 3) = 9$ |
| 140 | + \item $\mathscr{A}(2, 4) = 11$ |
| 141 | + \end{itemize} |
| 142 | +\end{frame} |
| 143 | + |
| 144 | +\begin{frame}{Rekursion: Ackermannfunktion} |
| 145 | + \begin{itemize} |
| 146 | + \item $\mathscr{A}(4, 2)$ ist eine Zahl mit \textbf{19729} Dezimalstellen |
| 147 | + \end{itemize} |
| 148 | +\end{frame} |
| 149 | + |
| 150 | + |
| 151 | +\subsubsection{Iteration vs. Rekursion} |
| 152 | + |
| 153 | +\begin{frame}[fragile]{Iteration vs. Rekursion} |
| 154 | + Alternativ zur rekursiven Variante von \texttt{factorial()}\dots |
| 155 | + \begin{exampleblock}{} |
| 156 | + \begin{lstlisting}[language=Java,basicstyle=\scriptsize] |
| 157 | +int factorial(int n) { |
| 158 | + int result = 1; |
| 159 | + for (int i = 2; i <= n; ++i) { |
| 160 | + result *= i; |
| 161 | + } |
| 162 | + return result; |
| 163 | +} |
| 164 | + \end{lstlisting} |
| 165 | + |
| 166 | + \end{exampleblock} |
| 167 | +\end{frame} |
| 168 | + |
| 169 | +\begin{frame}{Zusammenfassung} |
| 170 | + \begin{itemize} |
| 171 | + \item \textbf{Rekursion} kann speicheraufwendig werden, da jedes Mal eine neue Instanz der Methode aufgerufen wird |
| 172 | + \begin{itemize} |
| 173 | + \item Stack kann überlaufen! |
| 174 | + \end{itemize} |
| 175 | + \item Nicht immer klar, ob die Berechnung terminiert |
| 176 | + \item Rekursion ist bei manchen Problemen eine elegante Lösung |
| 177 | + \item Es gibt nicht immer eine \quotes{iterative Lösung} (siehe \textit{Ackermannfunktion}) |
| 178 | + \end{itemize} |
| 179 | +\end{frame} |
| 180 | + |
| 181 | +\begin{frame}{Java API} |
| 182 | + \begin{itemize} |
| 183 | + \item Die \textbf{Java API} ist eine Sammlung von Klassen/Paketen für häufig benötigte Funktionalitäten |
| 184 | + |
| 185 | + \begin{itemize} |
| 186 | + \item \texttt{java.lang}: Basisfunktionalität |
| 187 | + \item \texttt{java.util}: Java Collections Framework |
| 188 | + \item \texttt{java.io}: Ein- und Ausgabe |
| 189 | + \end{itemize} |
| 190 | + |
| 191 | + \vspace{.2in} |
| 192 | + |
| 193 | + \item Das \textbf{Java Collections Framework} enthält u.a. |
| 194 | + \begin{itemize} |
| 195 | + \item \texttt{Map<K,V>}, \texttt{Set<E>}\dots |
| 196 | + \item \texttt{Queue<E>}, \texttt{Deque<E>}, \texttt{Stack<E>}\dots |
| 197 | + \item \texttt{List<E>}, \texttt{LinkedList<E>}\dots |
| 198 | + \end{itemize} |
| 199 | + |
| 200 | + \vspace{.2in} |
| 201 | + |
| 202 | + \item \quotes{Das Rad muss nicht neu erfunden werden.} |
| 203 | + |
| 204 | + \end{itemize} |
| 205 | +\end{frame} |
| 206 | + |
| 207 | +\begin{frame}{Sets und Maps} |
| 208 | + \begin{block}{} |
| 209 | + \begin{itemize} |
| 210 | + \item Ein \textbf{Set} stellt eine Menge (im mathematischen Sinne) dar |
| 211 | + \item Sammlung von Objekten, \textit{ohne Duplikate} |
| 212 | + \end{itemize} |
| 213 | + \end{block} |
| 214 | + |
| 215 | + \begin{block}{} |
| 216 | + \begin{itemize} |
| 217 | + \item Eine \textbf{Map} stellt eine Abbildung von Schlüsseln (keys) auf Werte (values) dar |
| 218 | + \item Beispiel: \texttt{String} als key, \texttt{Student} als value |
| 219 | + \end{itemize} |
| 220 | + |
| 221 | + \end{block} |
| 222 | +\end{frame} |
| 223 | + |
| 224 | +\begin{frame}[fragile]{Sets} |
| 225 | + \begin{lstlisting}[language=Java] |
| 226 | +Set<String> names = new HashSet<>(); |
| 227 | + |
| 228 | +names.add("Alice"); |
| 229 | +names.add("Eve"); |
| 230 | +names.add("Bob"); |
| 231 | +names.add("Eve"); |
| 232 | + |
| 233 | +it = names.iterator(); |
| 234 | +String name; |
| 235 | +while (it.hasNext()) { |
| 236 | + name = it.next(); |
| 237 | + System.out.println(name); |
| 238 | +} |
| 239 | + \end{lstlisting} |
| 240 | + |
| 241 | +\end{frame} |
| 242 | + |
| 243 | +\begin{frame}[fragile]{Sets} |
| 244 | + \begin{exampleblock}{} |
| 245 | + \begin{lstlisting}[language=Java] |
| 246 | +Bob |
| 247 | +Eve |
| 248 | +Alice |
| 249 | + \end{lstlisting} |
| 250 | + \end{exampleblock} |
| 251 | + |
| 252 | +\end{frame} |
| 253 | + |
| 254 | + |
| 255 | +\begin{frame}[fragile]{Maps} |
| 256 | + \begin{lstlisting}[language=Java] |
| 257 | +Map<String, Integer> mountains = new HashMap<>(); |
| 258 | + |
| 259 | +mountains.put("Everest", 8848); |
| 260 | +mountains.put("K2", 8611); |
| 261 | +mountains.put("Kangchenjunga", 8586); |
| 262 | +mountains.put("Lhotse", 8516); |
| 263 | + |
| 264 | +System.out.println(mountains.get("Everest")); |
| 265 | + \end{lstlisting} |
| 266 | +\end{frame} |
| 267 | + |
| 268 | +\begin{frame}[fragile]{Maps} |
| 269 | + |
| 270 | + \begin{exampleblock}{} |
| 271 | + \begin{lstlisting}[language=Java] |
| 272 | +8848 |
| 273 | + \end{lstlisting} |
| 274 | + |
| 275 | + \end{exampleblock} |
| 276 | +\end{frame} |
| 277 | + |
| 278 | + |
| 279 | +\begin{frame}[fragile]{Stack} |
| 280 | + \begin{lstlisting}[language=Java] |
| 281 | +Stack<String> books = new Stack<>(); |
| 282 | + |
| 283 | +books.push("Modern Operating Systems"); |
| 284 | +books.push("The Magic Garden Explained"); |
| 285 | + |
| 286 | +System.out.println(books.peek()); |
| 287 | +books.pop(); |
| 288 | + |
| 289 | +books.push("The Art of Game Design"); |
| 290 | + |
| 291 | +String next; |
| 292 | +while (!books.empty()) { |
| 293 | + next = books.pop(); |
| 294 | + System.out.println(next); |
| 295 | +} |
| 296 | + \end{lstlisting} |
| 297 | + |
| 298 | +\end{frame} |
| 299 | + |
| 300 | +\begin{frame}[fragile]{Stack} |
| 301 | + \begin{exampleblock}{} |
| 302 | + \begin{lstlisting}[language=Java] |
| 303 | +The Magic Garden Explained |
| 304 | +The Art of Game Design |
| 305 | +Modern Operating Systems |
| 306 | + \end{lstlisting} |
| 307 | + \end{exampleblock} |
| 308 | + |
| 309 | +\end{frame} |
| 310 | + |
| 311 | +\begin{frame}{Read the fine manual} |
| 312 | + \Large{\url{https://docs.oracle.com/javase/8/docs/api}} |
| 313 | +\end{frame} |
| 314 | + |
| 315 | +\appendix |
| 316 | +\beginbackup |
| 317 | + |
| 318 | +\begin{frame}{Fragen?} |
| 319 | + \begin{figure} |
| 320 | + \includegraphics[scale=.6]{img/additionalquestions.jpg} |
| 321 | + \end{figure} |
| 322 | +\end{frame} |
| 323 | + |
| 324 | +\begin{frame}{Bis nächste Woche!} |
| 325 | + \begin{figure} |
| 326 | + \includegraphics[scale=.4]{img/team_chat.png} |
| 327 | + \caption{\footnotesize{xkcd.com}} |
| 328 | + \end{figure} |
| 329 | +\end{frame} |
| 330 | + |
| 331 | +\backupend |
| 332 | + |
| 333 | +\end{document} |
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