% !TEX program = xelatex

\documentclass[dvipsnames,14pt,t,xelatex]{beamer}

\usepackage{../slides}

\usepackage{../graphics}

\usepackage{../langs}

%%\usepackage{../data}

\usetikzlibrary{shapes}

\usepackage[export]{adjustbox}

\hfuzz=220pt 

%\setmonofont[Scale=.88]{Consolas}

%\newfontfamily{\consolas}{Consolas}

\lstset{language=Scala,

        style=mystyle,

        numbersep=0pt,

        numbers=none,

        xleftmargin=0mm}

\newcommand{\bl}[1]{\textcolor{blue}{#1}}     

% beamer stuff 

\renewcommand{\slidecaption}{PEP (Scala) 03, King's College London}

\newcommand{\UParrow}[3]{%

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\begin{document}

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\begin{frame}[t]

\frametitle{%

  \begin{tabular}{@ {}c@ {}}

  \\[5mm]

  \huge PEP Scala (3) 

  \end{tabular}}

  \normalsize

  \begin{center}

  \begin{tabular}{ll}

    Email:  & christian.urban at kcl.ac.uk\\

    Office: & N\liningnums{7.07} (North Wing, Bush House)\bigskip\\

    Slides \& Code: & KEATS\bigskip\\

    Office Hours: &  Thursdays 12:00 -- 14:00\\

    Additionally: & (for Scala) Tuesdays 10:45 -- 11:45\\ 

  \end{tabular}

  \end{center}

\end{frame}

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\begin{frame}[c]

\frametitle{Preliminary 6}

Raw marks (261 submissions):\bigskip

\begin{itemize}

\item 3\%: \hspace{4mm}219

\item 2\%: \hspace{4mm}19

\item 1\%: \hspace{4mm}0

\item 0\%: \hspace{4mm}23 \;(4 no submission)

\end{itemize}  

\end{frame}

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\begin{frame}[c,fragile]

\begin{lstlisting}[language=Scala, numbers=none, xleftmargin=-1mm]

def collatz(n: Long) : Long =

  {

    val toReturn = collatzHelper(n, 0)

    toReturn

  } 

\end{lstlisting}

\pause

\bigskip

\rule{11cm}{0.3mm}

\bigskip

\begin{lstlisting}[language=Scala, numbers=none, xleftmargin=-1mm]

def collatz(n: Long) : Long =

  collatzHelper(n, 0)

\end{lstlisting}

\end{frame}

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\begin{frame}[c,fragile]

\frametitle{Default Arguments}

\small

\begin{lstlisting}[language=Scala, numbers=none, xleftmargin=-3mm]

def collatzHelper(n: Int, a: Int = 0) : Int = ...

collatzHelper(n, 3)

collatzHelper(n, 0)

collatzHelper(n)   // a = 0   

\end{lstlisting}

\DOWNarrow{1}{10.7}{3.4}

\end{frame}

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\begin{frame}[c,fragile]

\frametitle{Last Week: Options \& HO Funs.}

\begin{lstlisting}[language=Scala, numbers=none, xleftmargin=-1mm]

List(7,2,3,4,5,6).find(_ < 4)

res: Option[Int] = Some(2)

List(5,6,7,8,9).find(_ < 4)

res: Option[Int] = None

List(1,2,3,4,5).map(x => x * x)

res: List[Int] = List(1, 4, 9, 16, 25)

\end{lstlisting}

  \end{frame}

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\begin{frame}[c,fragile]

\frametitle{Web-Crawler (1)}

\small

\begin{lstlisting}[language=Scala, numbers=none, xleftmargin=-7mm]

def get_page(url: String) : String = {

Try(fromURL(url)("ISO-8859-1").take(10000).mkString)

   .getOrElse { println(s" Problem with: $url"); ""}

}

\end{lstlisting}

\end{frame}

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\begin{frame}[c,fragile]

\frametitle{Web-Crawler (2)}

\small

\begin{lstlisting}[language=Scala, numbers=none, 

                    xleftmargin=-7mm, escapeinside={(*@}{@*)}]

val http_pattern = """(*@\textcolor{codegreen}{"}@*)https?://[\^(*@\textcolor{codegreen}{"}@*)]*(*@\textcolor{codegreen}{"}@*)""".r

val email_pattern = 

 """([a-z\d\.-]+)@([\da-z\.-]+)\.([a-z\.]{2,6})""".r

def unquote(s: String) = s.drop(1).dropRight(1)

def get_all_URLs(page: String): Set[String] = 

  http_pattern.findAllIn(page).map(unquote).toSet

  // returns all URLs in a page  

\end{lstlisting}

  \end{frame}

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\begin{frame}[c,fragile]

\frametitle{Web-Crawler (3)}

\small

\begin{lstlisting}[language=Scala, numbers=none, xleftmargin=-1mm]

def crawl(url: String, n: Int) : Unit = {

  if (n == 0) ()

  else {

    println(s"  Visiting: $n $url")

    val page = get_page(url)

    for (u <- get_all_URLs(page)) 

      crawl(u, n - 1)

  }

}

\end{lstlisting}

\end{frame}

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\begin{frame}[c,fragile]

\frametitle{Email Harvester}

\small

\begin{lstlisting}[language=Scala, numbers=none, xleftmargin=-3mm]

def emails(url: String, n: Int) : Set[String] = {

 if (n == 0) Set()

 else {

  println(s"  Visiting: $n $url")

  val page = get_page(url)

  val new_emails = 

    email_pattern.findAllIn(page).toSet

  new_emails ++ 

    (for (u <- get_all_URLs(page)) 

       yield emails(u, n - 1)).flatten

 }

} 

\end{lstlisting}

\end{frame}

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\begin{frame}[c]

\frametitle{Jumping Towers}

\begin{center}

\begin{tikzpicture}[scale=1.3]

  \draw[line width=1mm,cap=round] (0,0) -- (5,0);

  \draw[line width=1mm,cap=round] (0,1) -- (5,1);

  \draw[line width=1mm,cap=round] (0,0) -- (0,1);

  \node at (0.5,0.5) {\textbf{\Large 3}};

  \draw[line width=1mm,cap=round] (1,0) -- (1,1);

  \node at (1.5,0.5) {\textbf{\Large 4}};

  \draw[line width=1mm,cap=round] (2,0) -- (2,1);

  \node at (2.5,0.5) {\textbf{\Large 2}};

  \draw[line width=1mm,cap=round] (3,0) -- (3,1);

  \node at (3.5,0.5) {\textbf{\Large 0}};

  \draw[line width=1mm,cap=round] (4,0) -- (4,1);

  \node at (4.5,0.5) {\textbf{\Large 1}};

  \draw[line width=1mm,cap=round] (5,0) -- (5,1);

  \draw[->,line width=0.5mm,cap=round,out=90,in=90,relative] (0.5,1) to (1.5,1);

  \draw[->,line width=0.5mm,cap=round,out=90,in=90,relative] (0.5,1) to (2.5,1);

  \draw[->,line width=0.5mm,cap=round,out=90,in=90,relative] (0.5,1) to (3.5,1);

  \draw[->,line width=0.5mm,cap=round,out=-90,in=-90,relative] (2.5,0) to (3.5,0);

  \draw[->,line width=0.5mm,cap=round,out=-90,in=-90,relative] (2.5,0) to (4.5,0);

  \draw[->,line width=0.5mm,cap=round,out=90,in=90,relative] (4.5,1) to (5.7,1);

  \node at (5.7, 0.8) {End};

\end{tikzpicture}

\end{center}\bigskip

shortest: 3 $\rightarrow$ 4 $\rightarrow$ End

\end{frame}

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\begin{frame}[c]

\frametitle{``Children'' / moves}

\begin{center}

  \begin{tikzpicture}

    [grow=right,level distance=30mm,child anchor=north,line width=0.5mm]

  \node {$[3,4,2,0,1]$}

     child {node {$[0,1]$}}

     child {node {$[2,0,1]$}

        child {node {$[1]$} child [level distance=13mm] {node {End}}}

        child {node {$[0,1]$}}

     }

     child {node {$[4,2,0,1]$\ldots}};

\end{tikzpicture}

\end{center}

\end{frame}

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\begin{frame}[c,fragile]

\frametitle{Reverse Polish Notation}

{\Large\bl{$(3 + 1) * (2 + 9)$}}\bigskip

{\Large$\Rightarrow$}\bigskip

{\;\;\Large\bl{$3\;\;1\;+\;2\;\;9\;+\;*$}}

\end{frame}

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\begin{frame}[c,fragile]

\frametitle{Sudoku}

A very simple-minded version on 110 problems:\bigskip

\begin{itemize}

\item 1 core: 800 secs

\item 2 cores: 400 secs

\item 8 cores: 290 secs

\item 18 cores: 142 secs

\end{itemize}

\end{frame}

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\end{document}

\end{document}

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