# HG changeset patch # User Christian Urban # Date 1564649314 -3600 # Node ID e43f7e92ba26f89757c070a6b4ba0ae52be2373c # Parent 9e02167567711a4b169ad76ef995d8fefa25c982 updated diff -r 9e0216756771 -r e43f7e92ba26 cws/cw02.pdf Binary file cws/cw02.pdf has changed diff -r 9e0216756771 -r e43f7e92ba26 cws/cw02.tex --- a/cws/cw02.tex Wed Jul 24 15:18:44 2019 +0100 +++ b/cws/cw02.tex Thu Aug 01 09:48:34 2019 +0100 @@ -1,3 +1,4 @@ +% !TEX program = xelatex \documentclass{article} \usepackage{../style} \usepackage{disclaimer} @@ -13,8 +14,8 @@ \mbox{}\hfill\textit{ --- Frederick P.~Brooks (author of The Mythical Man-Month)}\bigskip \noindent -This coursework is worth 10\%. The first and second part are due -on 22 November at 11pm; the third, more advanced part, is due on 20 +This coursework is worth 10\%. The basic part is due +on 22 November at 11pm; the main part is due on 20 December at 11pm. You are asked to implement Scala programs for measuring similarity in texts, and for recommending movies according to a ratings list. Note the second part might include @@ -34,8 +35,9 @@ Like the C++ assignments, the Scala assignments will work like this: you push your files to GitHub and receive (after sometimes a long delay) some automated feedback. In the end we take a snapshot of the submitted files and -apply an automated marking script to them. +apply an automated marking script to them.\medskip +\noindent In addition, the Scala assignments come with a reference implementation in form of a \texttt{jar}-file. This allows you to run any test cases on your own computer. For example you can call Scala on @@ -82,7 +84,7 @@ \newpage -\subsection*{Part 1 (4 Marks, file docdiff.scala)} +\subsection*{Basic Part (4 Marks, file docdiff.scala)} It seems source code plagiarism---stealing and submitting someone else's code---is a serious problem at other @@ -167,7 +169,7 @@ \end{itemize}\bigskip -\subsection*{Part 2 (2 Marks, file danube.scala)} +\subsection*{Main Part (2 Marks, file danube.scala)} You are creating Danube.co.uk which you hope will be the next big thing in online movie renting. You know that you can save money by @@ -229,14 +231,14 @@ ratings below 4 and returns a list of (userID, movieID) pairs. The \pcode{process_movies} function returns a list of (movieID, title) pairs.\\ \mbox{}\hfill [1 Mark] -\end{itemize} - - -\subsection*{Part 3 (4 Marks, file danube.scala)} - -\subsection*{Tasks} - -\begin{itemize} +%\end{itemize} +% +% +%\subsection*{Part 3 (4 Marks, file danube.scala)} +% +%\subsection*{Tasks} +% +%\begin{itemize} \item[(3)] Implement a kind of grouping function that calculates a Map containing the userIDs and all the corresponding recommendations for this user (list of movieIDs). This should be implemented in a @@ -285,7 +287,7 @@ \mbox{}\hfill [1 Mark] \end{itemize} -\end{document} +\end{document} %%% Local Variables: %%% mode: latex diff -r 9e0216756771 -r e43f7e92ba26 cws/cw05.pdf Binary file cws/cw05.pdf has changed diff -r 9e0216756771 -r e43f7e92ba26 cws/cw05.tex --- a/cws/cw05.tex Wed Jul 24 15:18:44 2019 +0100 +++ b/cws/cw05.tex Thu Aug 01 09:48:34 2019 +0100 @@ -27,15 +27,17 @@ maximum of 30 seconds on my laptop. \DISCLAIMER{} +\newpage \subsection*{Reference Implementation} -As usual, this Scala assignment comes with a reference implementation in form of -two \texttt{jar}-files. You can download them from KEATS. They allow you to run any -test cases on your own computer. For example you can call Scala on the command line with the -option \texttt{-cp bf.jar} and then query any function from the -\texttt{bf.scala} template file. You have to -prefix the calls with \texttt{CW10a} and \texttt{CW10b}, respectively. For example +As usual, this Scala assignment comes with a reference implementation in +form of two \texttt{jar}-files. You can download them from KEATS. They +allow you to run any test cases on your own computer. For example you +can call Scala on the command line with the option \texttt{-cp bf.jar} +and then query any function from the \texttt{bf.scala} template file. +You have to prefix the calls with \texttt{CW10a} and \texttt{CW10b}, +respectively. For example \begin{lstlisting}[language={},xleftmargin=1mm,numbers=none,basicstyle=\ttfamily\small] @@ -76,7 +78,7 @@ * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * \end{lstlisting}%$ - +\newpage \subsection*{Part 1 (6 Marks)} @@ -106,7 +108,7 @@ \begin{center} \url{https://www.microsoft.com/en-us/p/brainf-ck/9nblgggzhvq5} -\end{center} +\end{center} \bigskip \noindent @@ -155,7 +157,7 @@ memory location \texttt{0}, and at \texttt{2} it stores \texttt{3}. The convention is that if we query the memory at a location that is \emph{not} defined in the \texttt{Map}, we return \texttt{0}. Write - a function, \texttt{sread}, that takes a memory (a \texttt{Map}) and + a `safe-read' function, \texttt{sread}, that takes a memory (a \texttt{Map}) and a memory pointer (an \texttt{Int}) as arguments, and `safely' reads the corresponding memory location. If the \texttt{Map} is not defined at the memory pointer, \texttt{sread} returns \texttt{0}. @@ -325,7 +327,7 @@ \end{figure} \end{itemize}\bigskip -\newpage +%%\newpage \subsection*{Part 2 (4 Marks)} diff -r 9e0216756771 -r e43f7e92ba26 marking1/drumb_test.sh --- a/marking1/drumb_test.sh Wed Jul 24 15:18:44 2019 +0100 +++ b/marking1/drumb_test.sh Thu Aug 01 09:48:34 2019 +0100 @@ -98,7 +98,7 @@ if [ $tsts -eq 0 ] then echo " get_first_price(\"GOOG\", 1980) == None" | tee -a $out - echo " get_first_price(\"GOOG\", 2010) == Some(311.349976)" | tee -a $out + echo " get_first_price(\"GOOG\", 2010) == Some(312.204773)" | tee -a $out if (scala_assert "drumb.scala" "drumb_test2.scala") then @@ -118,9 +118,9 @@ echo " List(Some(12.241)), List(Some(38.188)))" | tee -a $out echo " " | tee -a $out echo " get_prices(List(\"GOOG\", \"AAPL\"), 2010 to 2012) ==" | tee -a $out - echo " List(List(Some(311.349976), Some(20.544939))," | tee -a $out - echo " List(Some(300.222351), Some(31.638695))," | tee -a $out - echo " List(Some(330.555054), Some(39.478039)))" | tee -a $out + echo " List(List(Some(312.204773), Some(26.782711))," | tee -a $out + echo " List(Some(301.0466), Some(41.244694))," | tee -a $out + echo " List(Some(331.462585), Some(51.464207)))" | tee -a $out if (scala_assert "drumb.scala" "drumb_test3.scala") then @@ -155,8 +155,8 @@ if [ $tsts -eq 0 ] then echo -e " get_deltas(get_prices(List(\"GOOG\", \"AAPL\"), 2010 to 2012)) == " | tee -a $out - echo -e " List(List(Some(-0.03573992567129673), Some(0.539975124774038)), " | tee -a $out - echo -e " List(Some(0.10103412653643493), Some(0.24777709700099845)))" | tee -a $out + echo -e " List(List(Some(-0.03573991804411003), Some(0.539974575389325)), " | tee -a $out + echo -e " List(Some(0.10103414222249969), Some(0.24777764141006836)))" | tee -a $out echo -e "" | tee -a $out echo -e " get_deltas(get_prices(List(\"BIDU\"), 2004 to 2008)) == " | tee -a $out echo -e " List(List(None), List(None), " | tee -a $out @@ -203,7 +203,7 @@ echo -e " investment(List(\"GOOG\", \"AAPL\", \"BIDU\"), 2000 to 2005, 100) == 113" | tee -a $out echo -e " investment(List(\"GOOG\", \"AAPL\", \"BIDU\"), 2000 to 2006, 100) == 254" | tee -a $out echo -e " investment(List(\"GOOG\", \"AAPL\", \"BIDU\"), 2000 to 2007, 100) == 349" | tee -a $out - echo -e " investment(List(\"GOOG\", \"AAPL\", \"BIDU\"), 1990 to 2017, 100) == 83061" | tee -a $out + echo -e " investment(List(\"GOOG\", \"AAPL\", \"BIDU\"), 1990 to 2017, 100) == 11504" | tee -a $out if (scala_assert "drumb.scala" "drumb_test7.scala") diff -r 9e0216756771 -r e43f7e92ba26 marking1/drumb_test2.scala --- a/marking1/drumb_test2.scala Wed Jul 24 15:18:44 2019 +0100 +++ b/marking1/drumb_test2.scala Thu Aug 01 09:48:34 2019 +0100 @@ -1,5 +1,12 @@ - -assert(get_first_price("GOOG", 1980) == None) +def myassert(cond : => Boolean) = { + try { + assert(cond) + } catch { + case _ : Throwable => System.exit(1) + } +} -assert(get_first_price("GOOG", 2010) == Some(311.349976)) +myassert(get_first_price("GOOG", 1980) == None) +myassert(get_first_price("GOOG", 2010) == Some(312.204773)) + diff -r 9e0216756771 -r e43f7e92ba26 marking1/drumb_test3.scala --- a/marking1/drumb_test3.scala Wed Jul 24 15:18:44 2019 +0100 +++ b/marking1/drumb_test3.scala Thu Aug 01 09:48:34 2019 +0100 @@ -1,4 +1,17 @@ -assert(get_prices(List("GOOG", "AAPL"), 2010 to 2012) == - List(List(Some(311.349976), Some(20.544939)), - List(Some(300.222351), Some(31.638695)), - List(Some(330.555054), Some(39.478039)))) +def myassert(cond : => Boolean) = { + try { + assert(cond) + } catch { + case _ : Throwable => System.exit(1) + } +} + +myassert(get_prices(List("BIDU"), 2004 to 2008) == + List(List(None), List(None), List(Some(6.35)), + List(Some(12.241)), List(Some(38.188)))) + + +myassert(get_prices(List("GOOG", "AAPL"), 2010 to 2012) == + List(List(Some(312.204773), Some(26.782711)), + List(Some(301.0466), Some(41.244694)), + List(Some(331.462585), Some(51.464207)))) diff -r 9e0216756771 -r e43f7e92ba26 marking1/drumb_test4.scala --- a/marking1/drumb_test4.scala Wed Jul 24 15:18:44 2019 +0100 +++ b/marking1/drumb_test4.scala Thu Aug 01 09:48:34 2019 +0100 @@ -1,6 +1,12 @@ - +def myassert(cond : => Boolean) = { + try { + assert(cond) + } catch { + case _ : Throwable => System.exit(1) + } +} -assert(get_delta(None, None) == None) -assert(get_delta(Some(50.0), None) == None) -assert(get_delta(None, Some(100.0)) == None) -assert(get_delta(Some(50.0), Some(100.0)) == Some(1.0)) +myassert(get_delta(None, None) == None) +myassert(get_delta(Some(50.0), None) == None) +myassert(get_delta(None, Some(100.0)) == None) +myassert(get_delta(Some(50.0), Some(100.0)) == Some(1.0)) diff -r 9e0216756771 -r e43f7e92ba26 marking1/drumb_test5.scala --- a/marking1/drumb_test5.scala Wed Jul 24 15:18:44 2019 +0100 +++ b/marking1/drumb_test5.scala Thu Aug 01 09:48:34 2019 +0100 @@ -1,12 +1,19 @@ +def myassert(cond : => Boolean) = { + try { + assert(cond) + } catch { + case _ : Throwable => System.exit(1) + } +} // get_prices(List("GOOG", "AAPL"), 2010 to 2012) -val urban_prices = List(List(Some(311.349976), Some(20.544939)), - List(Some(300.222351), Some(31.638695)), - List(Some(330.555054), Some(39.478039))) +val urban_prices = List(List(Some(312.204773), Some(26.782711)), + List(Some(301.0466), Some(41.244694)), + List(Some(331.462585), Some(51.464207))) -assert(get_deltas(urban_prices) == List(List(Some(-0.03573992567129673), Some(0.539975124774038)), - List(Some(0.10103412653643493), Some(0.24777709700099845)))) +myassert(get_deltas(urban_prices) == List(List(Some(-0.03573991804411003), Some(0.539974575389325)), + List(Some(0.10103414222249969), Some(0.24777764141006836)))) //get_prices(List("BIDU"), 2004 to 2008) @@ -15,6 +22,6 @@ List(Some(38.188))) -assert(get_deltas(urban_prices2) == List(List(None), List(None), +myassert(get_deltas(urban_prices2) == List(List(None), List(None), List(Some(0.9277165354330709)), List(Some(2.119679764725104)))) diff -r 9e0216756771 -r e43f7e92ba26 marking1/drumb_test6.scala --- a/marking1/drumb_test6.scala Wed Jul 24 15:18:44 2019 +0100 +++ b/marking1/drumb_test6.scala Thu Aug 01 09:48:34 2019 +0100 @@ -1,9 +1,18 @@ //val urban_deltas = get_deltas(get_prices(List("GOOG", "AAPL"), 2010 to 2012)) -val ds_urban = List(List(Some(-0.03573992567129673), Some(0.539975124774038)), - List(Some(0.10103412653643493), Some(0.24777709700099845))) +def myassert(cond : => Boolean) = { + try { + assert(cond) + } catch { + case _ : Throwable => System.exit(1) + } +} + + +val ds_urban = List(List(Some(-0.03573991804411003), Some(0.539974575389325)), + List(Some(0.10103414222249969), Some(0.24777764141006836))) -assert(yearly_yield(ds_urban, 100, 0) == 125) -assert(yearly_yield(ds_urban, 100, 1) == 117) +myassert(yearly_yield(ds_urban, 100, 0) == 125) +myassert(yearly_yield(ds_urban, 100, 1) == 117) diff -r 9e0216756771 -r e43f7e92ba26 marking1/drumb_test7.scala --- a/marking1/drumb_test7.scala Wed Jul 24 15:18:44 2019 +0100 +++ b/marking1/drumb_test7.scala Thu Aug 01 09:48:34 2019 +0100 @@ -1,10 +1,18 @@ +def myassert(cond : => Boolean) = { + try { + assert(cond) + } catch { + case _ : Throwable => System.exit(1) + } +} -assert(investment(List("GOOG", "AAPL", "BIDU"), 2000 to 2000, 100) == 100) -assert(investment(List("GOOG", "AAPL", "BIDU"), 2000 to 2001, 100) == 27) -assert(investment(List("GOOG", "AAPL", "BIDU"), 2000 to 2002, 100) == 42) -assert(investment(List("GOOG", "AAPL", "BIDU"), 2000 to 2003, 100) == 27) -assert(investment(List("GOOG", "AAPL", "BIDU"), 2000 to 2004, 100) == 38) -assert(investment(List("GOOG", "AAPL", "BIDU"), 2000 to 2005, 100) == 113) -assert(investment(List("GOOG", "AAPL", "BIDU"), 2000 to 2006, 100) == 254) -assert(investment(List("GOOG", "AAPL", "BIDU"), 2000 to 2007, 100) == 349) -assert(investment(List("GOOG", "AAPL", "BIDU"), 1990 to 2017, 100) == 83061) + +myassert(investment(List("GOOG", "AAPL", "BIDU"), 2000 to 2000, 100) == 100) +myassert(investment(List("GOOG", "AAPL", "BIDU"), 2000 to 2001, 100) == 27) +myassert(investment(List("GOOG", "AAPL", "BIDU"), 2000 to 2002, 100) == 42) +myassert(investment(List("GOOG", "AAPL", "BIDU"), 2000 to 2003, 100) == 27) +myassert(investment(List("GOOG", "AAPL", "BIDU"), 2000 to 2004, 100) == 38) +myassert(investment(List("GOOG", "AAPL", "BIDU"), 2000 to 2005, 100) == 113) +myassert(investment(List("GOOG", "AAPL", "BIDU"), 2000 to 2006, 100) == 254) +myassert(investment(List("GOOG", "AAPL", "BIDU"), 2000 to 2007, 100) == 349) +myassert(investment(List("GOOG", "AAPL", "BIDU"), 1990 to 2017, 100) == 11504) diff -r 9e0216756771 -r e43f7e92ba26 progs/lecture1.scala --- a/progs/lecture1.scala Wed Jul 24 15:18:44 2019 +0100 +++ b/progs/lecture1.scala Thu Aug 01 09:48:34 2019 +0100 @@ -37,12 +37,13 @@ List(1,2,3,1) Set(1,2,3,1) +// ranges 1 to 10 (1 to 10).toList (1 until 10).toList -// an element in a list +// picking an element in a list val lst = List(1, 2, 3, 1) lst(0) lst(2) @@ -52,8 +53,8 @@ 1 :: 2 :: 3 :: Nil List(1, 2, 3) ::: List(4, 5, 6) -// Equality is structural -//======================== +// Equality in Scala is structural +//================================= val a = "Dave" val b = "Dave" @@ -76,13 +77,16 @@ println("test") -val tst = "This is a " + "test\n" +val tst = "This is a " ++ "test" +print(tst) println(tst) val lst = List(1,2,3,1) println(lst.toString) + +println(lst.mkString) println(lst.mkString(",")) println(lst.mkString(", ")) @@ -90,6 +94,9 @@ // some methods take more than one argument println(lst.mkString("{", ",", "}")) +// (in this case .mkString can take no, one, +// or three arguments...this has to do with +// default arguments) // Conversion methods @@ -97,6 +104,7 @@ List(1,2,3,1).toString List(1,2,3,1).toSet + "hello".toList.tail 1.toDouble @@ -119,27 +127,31 @@ "abcdefg".startsWith("abc") -// Types (slide) -//=============== +// Types (see slide) +//=================== /* Scala is a strongly typed language - * some base types + * base types Int, Long, BigInt, Float, Double String, Char - Boolean + Boolean... - * some compound types + * compound types - List[Int], + List[Int] Set[Double] Pairs: (Int, String) List[(BigInt, String)] Option[Int] + + * user-defined types (later) + */ +// you can make the type of a value explicit val name: String = "leo" @@ -153,6 +165,7 @@ // required: Double // math.sqrt("64") + // Pairs/Tuples //============== @@ -174,7 +187,11 @@ def square(x: Int) : Int = x * x def str(x: Int) : String = x.toString + +incr(3) +double(4) square(6) +str(3) // The general scheme for a function: you have to give a type @@ -195,12 +212,21 @@ else n + n } +def another_silly(x: Int, y: String) : String = { + if (x <= 12) y + else x.toString +} + +another_silly(2, "two") +another_silly(12, "twelf") +another_silly(20, "twenty") + // If-Conditionals //================= // - Scala does not have a then-keyword -// - both if-else branches need to be present +// - !both if-else branches need to be present! def fact(n: Int) : Int = if (n == 0) 1 else n * fact(n - 1) @@ -250,7 +276,7 @@ // Option type //============= -//in Java if something unusually happens, you return null +//in Java if something unusually happens, you return null or something // //in Scala you use Options instead // - if the value is present, you use Some(value) @@ -269,7 +295,7 @@ import scala.util._ import io.Source -val my_url = "https://nms.imperial.ac.uk/christian.urban/" +val my_url = "https://nms.kcl.ac.uk/christian.urban/" Source.fromURL(my_url).mkString @@ -299,7 +325,7 @@ Try(Some(Source.fromFile(name).getLines.toList)).getOrElse(None) get_contents("text.txt") - +get_contents("test.txt") // String Interpolations @@ -346,6 +372,8 @@ m <- (1 to 10).toList) yield m * n +// you can assign the result of a for-comprehension +// to a value val mult_table = for (n <- (1 to 10).toList; m <- (1 to 10).toList) yield m * n @@ -426,10 +454,11 @@ for (c <- lst) println(c) // Aside: concurrency -// (ONLY WORKS OUT-OF-THE-BOX IN SCALA 2.11.8, not in SCALA 2.12) -// (would need to have this wrapped into a function, or -// REPL called with scala -Yrepl-class-based) +// (scala <<..parallel_collections...>> -Yrepl-class-based) for (n <- (1 to 10)) println(n) + +import scala.collection.parallel.CollectionConverters._ + for (n <- (1 to 10).par) println(n) @@ -456,6 +485,7 @@ // Q: Count how many elements are in the intersections of two sets? +// A; IMPROPER WAY (mutable counter) def count_intersection(A: Set[Int], B: Set[Int]) : Int = { var count = 0 diff -r 9e0216756771 -r e43f7e92ba26 progs/lecture2.scala --- a/progs/lecture2.scala Wed Jul 24 15:18:44 2019 +0100 +++ b/progs/lecture2.scala Thu Aug 01 09:48:34 2019 +0100 @@ -18,9 +18,7 @@ time_needed(10, for (n <- list) yield n + 42) time_needed(10, for (n <- list.par) yield n + 42) -// (ONLY WORKS OUT-OF-THE-BOX IN SCALA 2.11.8, not in SCALA 2.12) -// (would need to have this wrapped into a function, or -// REPL called with scala -Yrepl-class-based) +// (needs a library and 'magic' option -Yrepl-class-based) // Just for Fun: Mutable vs Immutable @@ -124,7 +122,8 @@ lst.map(square) -// this is actually what for is defined at in Scala +// this is actually how for-comprehensions +// defined as in Scala lst.map(n => square(n)) for (n <- lst) yield square(n) @@ -227,12 +226,13 @@ -// Option type -//============= +// Option type (again) +//===================== -//in Java if something unusually happens, you return null; +// remember, in Java if something unusually happens, +// you return null; // -//in Scala you use Option +// in Scala you use Option // - if the value is present, you use Some(value) // - if no value is present, you use None @@ -295,7 +295,7 @@ val lst = List("12345", "foo", "5432", "bar", "x21", "456") for (x <- lst) yield get_me_an_int(x) -// summing all the numbers +// summing up all the numbers lst.map(get_me_an_int).flatten.sum lst.map(get_me_an_int).flatten.sum @@ -419,7 +419,7 @@ fav_colour(Green) -// ... a bit more useful: Roman Numerals +// ... a tiny bit more useful: Roman Numerals abstract class RomanDigit case object I extends RomanDigit @@ -434,6 +434,7 @@ List(X,I) +/* I -> 1 II -> 2 III -> 3 @@ -444,6 +445,7 @@ VIII -> 8 IX -> 9 X -> X +*/ def RomanNumeral2Int(rs: RomanNumeral): Int = rs match { case Nil => 0 @@ -510,10 +512,8 @@ println(people.sortWith(superior).mkString("\n")) -print("123\\n456") - -// Tail recursion +// Tail Recursion //================ @@ -565,6 +565,7 @@ val http_pattern = """"https?://[^"]*"""".r val email_pattern = """([a-z0-9_\.-]+)@([\da-z\.-]+)\.([a-z\.]{2,6})""".r +//test case: //email_pattern.findAllIn // ("foo bla christian@kcl.ac.uk 1234567").toList @@ -617,54 +618,57 @@ |..7.9.41.""".stripMargin.replaceAll("\\n", "") type Pos = (Int, Int) -val EmptyValue = '.' -val MaxValue = 9 +val emptyValue = '.' +val maxValue = 9 val allValues = "123456789".toList val indexes = (0 to 8).toList +def empty(game: String) = game.indexOf(emptyValue) +def isDone(game: String) = empty(game) == -1 +def emptyPosition(game: String) : Pos = + (empty(game) % maxValue, empty(game) / maxValue) -def empty(game: String) = game.indexOf(EmptyValue) -def isDone(game: String) = empty(game) == -1 -def emptyPosition(game: String) = (empty(game) % MaxValue, empty(game) / MaxValue) - - -def get_row(game: String, y: Int) = indexes.map(col => game(y * MaxValue + col)) -def get_col(game: String, x: Int) = indexes.map(row => game(x + row * MaxValue)) +def get_row(game: String, y: Int) = indexes.map(col => game(y * maxValue + col)) +def get_col(game: String, x: Int) = indexes.map(row => game(x + row * maxValue)) def get_box(game: String, pos: Pos): List[Char] = { def base(p: Int): Int = (p / 3) * 3 val x0 = base(pos._1) val y0 = base(pos._2) - val ys = (y0 until y0 + 3).toList - (x0 until x0 + 3).toList.flatMap(x => ys.map(y => game(x + y * MaxValue))) -} + for (x <- (x0 until x0 + 3).toList; + y <- (y0 until y0 + 3).toList) yield game(x + y * maxValue) +} //get_row(game0, 0) //get_row(game0, 1) //get_box(game0, (3,1)) -def update(game: String, pos: Int, value: Char): String = game.updated(pos, value) +def update(game: String, pos: Int, value: Char): String = + game.updated(pos, value) def toAvoid(game: String, pos: Pos): List[Char] = (get_col(game, pos._1) ++ get_row(game, pos._2) ++ get_box(game, pos)) -def candidates(game: String, pos: Pos): List[Char] = allValues diff toAvoid(game,pos) +def candidates(game: String, pos: Pos): List[Char] = + allValues.diff(toAvoid(game, pos)) -//candidates(game0, (0,0)) +//candidates(game0, (0, 0)) -def pretty(game: String): String = "\n" + (game sliding (MaxValue, MaxValue) mkString "\n") +def pretty(game: String): String = + "\n" ++ (game.sliding(maxValue, maxValue).mkString("\n")) def search(game: String): List[String] = { if (isDone(game)) List(game) else - candidates(game, emptyPosition(game)).map(c => search(update(game, empty(game), c))).toList.flatten + candidates(game, emptyPosition(game)). + map(c => search(update(game, empty(game), c))).flatten } - +// an easy game val game1 = """23.915... |...2..54. |6.7...... @@ -676,7 +680,7 @@ |...329..1""".stripMargin.replaceAll("\\n", "") -// game that is in the hard category +// a game that is in the sligtly harder category val game2 = """8........ |..36..... |.7..9.2.. @@ -687,7 +691,7 @@ |..85...1. |.9....4..""".stripMargin.replaceAll("\\n", "") -// game with multiple solutions +// a game with multiple solutions val game3 = """.8...9743 |.5...8.1. |.1....... @@ -707,7 +711,7 @@ val start = System.nanoTime() for (j <- 1 to i) code val end = System.nanoTime() - ((end - start) / i / 1.0e9) + " secs" + s"${(end - start) / i / 1.0e9} secs" } search(game2).map(pretty) diff -r 9e0216756771 -r e43f7e92ba26 progs/sudoku.scala --- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/progs/sudoku.scala Thu Aug 01 09:48:34 2019 +0100 @@ -0,0 +1,236 @@ +// Sudoku +//======== + +object Sudoku extends App { + +import scala.collection.parallel.CollectionConverters._ + +type Pos = (Int, Int) +val emptyValue = '.' +val maxValue = 9 + +val allValues = "123456789".toList +val indexes = (0 to 8).toList + + +def empty(game: String) = game.indexOf(emptyValue) +def isDone(game: String) = empty(game) == -1 +def emptyPosition(game: String) : Pos = + (empty(game) % maxValue, empty(game) / maxValue) + + +def get_row(game: String, y: Int) = indexes.map(col => game(y * maxValue + col)) +def get_col(game: String, x: Int) = indexes.map(row => game(x + row * maxValue)) + +def get_box(game: String, pos: Pos): List[Char] = { + def base(p: Int): Int = (p / 3) * 3 + val x0 = base(pos._1) + val y0 = base(pos._2) + for (x <- (x0 until x0 + 3).toList; + y <- (y0 until y0 + 3).toList) yield game(x + y * maxValue) +} + + +//get_row(game0, 0) +//get_row(game0, 1) +//get_box(game0, (3,1)) + +def update(game: String, pos: Int, value: Char): String = + game.updated(pos, value) + +def toAvoid(game: String, pos: Pos): List[Char] = + (get_col(game, pos._1) ++ get_row(game, pos._2) ++ get_box(game, pos)) + +def candidates(game: String, pos: Pos): List[Char] = + allValues.diff(toAvoid(game, pos)) + +//candidates(game0, (0, 0)) + +//def pretty(game: String): String = +// "\n" ++ (game.sliding(maxValue, maxValue).mkString("\n")) + +def search(game: String): List[String] = { + if (isDone(game)) List(game) + else + candidates(game, emptyPosition(game)).par. + map(c => search(update(game, empty(game), c))).toList.flatten +} + +// two easy games +val game0 = """.14.6.3.. + |62...4..9 + |.8..5.6.. + |.6.2....3 + |.7..1..5. + |5....9.6. + |..6.2..3. + |1..5...92 + |..7.9.41.""".stripMargin.replaceAll("\\n", "") + +val game1 = """23.915... + |...2..54. + |6.7...... + |..1.....9 + |89.5.3.17 + |5.....6.. + |......9.5 + |.16..7... + |...329..1""".stripMargin.replaceAll("\\n", "") + + +// a game that is in the sligtly harder category +val game2 = """8........ + |..36..... + |.7..9.2.. + |.5...7... + |....457.. + |...1...3. + |..1....68 + |..85...1. + |.9....4..""".stripMargin.replaceAll("\\n", "") + +// a game with multiple solutions +val game3 = """.8...9743 + |.5...8.1. + |.1....... + |8....5... + |...8.4... + |...3....6 + |.......7. + |.3.5...8. + |9724...5.""".stripMargin.replaceAll("\\n", "") + +val hard_games = + List("85...24..72......9..4.........1.7..23.5...9...4...........8..7..17..........36.4.", + "..53.....8......2..7..1.5..4....53...1..7...6..32...8..6.5....9..4....3......97..", + "12..4......5.69.1...9...5.........7.7...52.9..3......2.9.6...5.4..9..8.1..3...9.4", + "...57..3.1......2.7...234......8...4..7..4...49....6.5.42...3.....7..9....18.....", + "7..1523........92....3.....1....47.8.......6............9...5.6.4.9.7...8....6.1.", + "1....7.9..3..2...8..96..5....53..9...1..8...26....4...3......1..4......7..7...3..", + "1...34.8....8..5....4.6..21.18......3..1.2..6......81.52..7.9....6..9....9.64...2", + "...92......68.3...19..7...623..4.1....1...7....8.3..297...8..91...5.72......64...", + ".6.5.4.3.1...9...8.........9...5...6.4.6.2.7.7...4...5.........4...8...1.5.2.3.4.", + "7.....4...2..7..8...3..8.799..5..3...6..2..9...1.97..6...3..9...3..4..6...9..1.35", + "....7..2.8.......6.1.2.5...9.54....8.........3....85.1...3.2.8.4.......9.7..6....", +// "4.....8.5.3..........7......2.....6.....8.4......1.......6.3.7.5..2.....1.4......", + "52...6.........7.13...........4..8..6......5...........418.........3..2...87.....", + "6.....8.3.4.7.................5.4.7.3..2.....1.6.......2.....5.....8.6......1....", + "48.3............71.2.......7.5....6....2..8.............1.76...3.....4......5....", +// "....14....3....2...7..........9...3.6.1.............8.2.....1.4....5.6.....7.8...", + "......52..8.4......3...9...5.1...6..2..7........3.....6...1..........7.4.......3.", + "6.2.5.........3.4..........43...8....1....2........7..5..27...........81...6.....", + ".524.........7.1..............8.2...3.....6...9.5.....1.6.3...........897........", + "6.2.5.........4.3..........43...8....1....2........7..5..27...........81...6.....", + ".923.........8.1...........1.7.4...........658.........6.5.2...4.....7.....9.....", + "6..3.2....5.....1..........7.26............543.........8.15........4.2........7..", + ".6.5.1.9.1...9..539....7....4.8...7.......5.8.817.5.3.....5.2............76..8...", + "..5...987.4..5...1..7......2...48....9.1.....6..2.....3..6..2.......9.7.......5..", + "3.6.7...........518.........1.4.5...7.....6.....2......2.....4.....8.3.....5.....", + "1.....3.8.7.4..............2.3.1...........958.........5.6...7.....8.2...4.......", + "6..3.2....4.....1..........7.26............543.........8.15........4.2........7..", + "....3..9....2....1.5.9..............1.2.8.4.6.8.5...2..75......4.1..6..3.....4.6.", + "45.....3....8.1....9...........5..9.2..7.....8.........1..4..........7.2...6..8..", + ".237....68...6.59.9.....7......4.97.3.7.96..2.........5..47.........2....8.......", + "..84...3....3.....9....157479...8........7..514.....2...9.6...2.5....4......9..56", + ".98.1....2......6.............3.2.5..84.........6.........4.8.93..5...........1..", + "..247..58..............1.4.....2...9528.9.4....9...1.........3.3....75..685..2...", +// "4.....8.5.3..........7......2.....6.....5.4......1.......6.3.7.5..2.....1.9......", + ".2.3......63.....58.......15....9.3....7........1....8.879..26......6.7...6..7..4", + "1.....7.9.4...72..8.........7..1..6.3.......5.6..4..2.........8..53...7.7.2....46", + "4.....3.....8.2......7........1...8734.......6........5...6........1.4...82......", + ".......71.2.8........4.3...7...6..5....2..3..9........6...7.....8....4......5....", + "6..3.2....4.....8..........7.26............543.........8.15........8.2........7..", + ".47.8...1............6..7..6....357......5....1..6....28..4.....9.1...4.....2.69.", + "......8.17..2........5.6......7...5..1....3...8.......5......2..4..8....6...3....", + "38.6.......9.......2..3.51......5....3..1..6....4......17.5..8.......9.......7.32", + "...5...........5.697.....2...48.2...25.1...3..8..3.........4.7..13.5..9..2...31..", + ".2.......3.5.62..9.68...3...5..........64.8.2..47..9....3.....1.....6...17.43....", + ".8..4....3......1........2...5...4.69..1..8..2...........3.9....6....5.....2.....", + "..8.9.1...6.5...2......6....3.1.7.5.........9..4...3...5....2...7...3.8.2..7....4", +// "4.....5.8.3..........7......2.....6.....5.8......1.......6.3.7.5..2.....1.8......", + "1.....3.8.6.4..............2.3.1...........958.........5.6...7.....8.2...4.......", + "1....6.8..64..........4...7....9.6...7.4..5..5...7.1...5....32.3....8...4........", + "249.6...3.3....2..8.......5.....6......2......1..4.82..9.5..7....4.....1.7...3...", + "...8....9.873...4.6..7.......85..97...........43..75.......3....3...145.4....2..1", +// "...5.1....9....8...6.......4.1..........7..9........3.8.....1.5...2..4.....36....", + "......8.16..2........7.5......6...2..1....3...8.......2......7..3..8....5...4....", + ".476...5.8.3.....2.....9......8.5..6...1.....6.24......78...51...6....4..9...4..7", + ".....7.95.....1...86..2.....2..73..85......6...3..49..3.5...41724................", + ".4.5.....8...9..3..76.2.....146..........9..7.....36....1..4.5..6......3..71..2..", + ".834.........7..5...........4.1.8..........27...3.....2.6.5....5.....8........1..", + "..9.....3.....9...7.....5.6..65..4.....3......28......3..75.6..6...........12.3.8", + ".26.39......6....19.....7.......4..9.5....2....85.....3..2..9..4....762.........4", + "2.3.8....8..7...........1...6.5.7...4......3....1............82.5....6...1.......", + "6..3.2....1.....5..........7.26............843.........8.15........8.2........7..", + "1.....9...64..1.7..7..4.......3.....3.89..5....7....2.....6.7.9.....4.1....129.3.", + ".........9......84.623...5....6...453...1...6...9...7....1.....4.5..2....3.8....9", + ".2....5938..5..46.94..6...8..2.3.....6..8.73.7..2.........4.38..7....6..........5", + "9.4..5...25.6..1..31......8.7...9...4..26......147....7.......2...3..8.6.4.....9.", + "...52.....9...3..4......7...1.....4..8..453..6...1...87.2........8....32.4..8..1.", + "53..2.9...24.3..5...9..........1.827...7.........981.............64....91.2.5.43.", + "1....786...7..8.1.8..2....9........24...1......9..5...6.8..........5.9.......93.4", + "....5...11......7..6.....8......4.....9.1.3.....596.2..8..62..7..7......3.5.7.2..", + ".47.2....8....1....3....9.2.....5...6..81..5.....4.....7....3.4...9...1.4..27.8..", + "......94.....9...53....5.7..8.4..1..463...........7.8.8..7.....7......28.5.26....", + ".2......6....41.....78....1......7....37.....6..412....1..74..5..8.5..7......39..", + "1.....3.8.6.4..............2.3.1...........758.........7.5...6.....8.2...4.......", + "2....1.9..1..3.7..9..8...2.......85..6.4.........7...3.2.3...6....5.....1.9...2.5", + "..7..8.....6.2.3...3......9.1..5..6.....1.....7.9....2........4.83..4...26....51.", + "...36....85.......9.4..8........68.........17..9..45...1.5...6.4....9..2.....3...", + "34.6.......7.......2..8.57......5....7..1..2....4......36.2..1.......9.......7.82", + "......4.18..2........6.7......8...6..4....3...1.......6......2..5..1....7...3....", + ".4..5..67...1...4....2.....1..8..3........2...6...........4..5.3.....8..2........", + ".......4...2..4..1.7..5..9...3..7....4..6....6..1..8...2....1..85.9...6.....8...3", + "8..7....4.5....6............3.97...8....43..5....2.9....6......2...6...7.71..83.2", + ".8...4.5....7..3............1..85...6.....2......4....3.26............417........", + "....7..8...6...5...2...3.61.1...7..2..8..534.2..9.......2......58...6.3.4...1....", + "......8.16..2........7.5......6...2..1....3...8.......2......7..4..8....5...3....", + ".2..........6....3.74.8.........3..2.8..4..1.6..5.........1.78.5....9..........4.", + ".52..68.......7.2.......6....48..9..2..41......1.....8..61..38.....9...63..6..1.9", + "....1.78.5....9..........4..2..........6....3.74.8.........3..2.8..4..1.6..5.....", + "1.......3.6.3..7...7...5..121.7...9...7........8.1..2....8.64....9.2..6....4.....", + "4...7.1....19.46.5.....1......7....2..2.3....847..6....14...8.6.2....3..6...9....", + "......8.17..2........5.6......7...5..1....3...8.......5......2..3..8....6...4....", + "963......1....8......2.5....4.8......1....7......3..257......3...9.2.4.7......9..", + "15.3......7..4.2....4.72.....8.........9..1.8.1..8.79......38...........6....7423", + "..........5724...98....947...9..3...5..9..12...3.1.9...6....25....56.....7......6", + "....75....1..2.....4...3...5.....3.2...8...1.......6.....1..48.2........7........", + "6.....7.3.4.8.................5.4.8.7..2.....1.3.......2.....5.....7.9......1....", + "....6...4..6.3....1..4..5.77.....8.5...8.....6.8....9...2.9....4....32....97..1..", + ".32.....58..3.....9.428...1...4...39...6...5.....1.....2...67.8.....4....95....6.", + "...5.3.......6.7..5.8....1636..2.......4.1.......3...567....2.8..4.7.......2..5..", + ".5.3.7.4.1.........3.......5.8.3.61....8..5.9.6..1........4...6...6927....2...9..", + "..5..8..18......9.......78....4.....64....9......53..2.6.........138..5....9.714.", + "..........72.6.1....51...82.8...13..4.........37.9..1.....238..5.4..9.........79.", + "...658.....4......12............96.7...3..5....2.8...3..19..8..3.6.....4....473..", + ".2.3.......6..8.9.83.5........2...8.7.9..5........6..4.......1...1...4.22..7..8.9", + ".5..9....1.....6.....3.8.....8.4...9514.......3....2..........4.8...6..77..15..6.", + ".....2.......7...17..3...9.8..7......2.89.6...13..6....9..5.824.....891..........", + "3...8.......7....51..............36...2..4....7...........6.13..452...........8..") + + + +//search(game0).map(pretty) +//search(game1).map(pretty) + +// for measuring time +def time_needed[T](i: Int, code: => T) = { + val start = System.nanoTime() + for (j <- 1 to i) code + val end = System.nanoTime() + s"${(end - start) / i / 1.0e9} secs" +} + +//search(game2).map(pretty) +//search(game3).distinct.length +println(time_needed(10, search(game0))) +println(time_needed(10, search(game1))) +println(time_needed(4, search(game2))) +println(time_needed(8, search(game3))) + +for (i <- 0 until hard_games.length) { + println(" " ++ hard_games(i)) + println(s"$i: ${time_needed(1, search(hard_games(i)))}") +} + +} \ No newline at end of file