diff -r 40657f9a4e4a -r 663c2a9108d1 testing2/docdiff.scala
--- a/testing2/docdiff.scala	Sat Oct 31 16:47:46 2020 +0000
+++ /dev/null	Thu Jan 01 00:00:00 1970 +0000
@@ -1,101 +0,0 @@
-// Preliminary Part about Code Similarity
-//========================================
-
-object CW7a {
-
-
-//(1) Complete the clean function below. It should find
-//    all words in a string using the regular expression
-//    \w+  and the library function
-//
-//         some_regex.findAllIn(some_string)
-//
-//    The words should be Returned as a list of strings.
-
-
-//def clean(s: String) : List[String] = ...
-def clean(s: String) : List[String] =
-    "\\w+".r.findAllIn(s).toList
-
-//(2) The function occurrences calculates the number of times
-//    strings occur in a list of strings. These occurrences should
-//    be calculated as a Map from strings to integers.
-
-
-//def occurrences(xs: List[String]): Map[String, Int] = ..
-def occurrences(xs: List[String]) : Map[String, Int] =
-    xs.groupBy(identity).view.mapValues(_.size).toMap
-
-//(3) This functions calculates the dot-product of two documents
-//    (list of strings). For this it calculates the occurrence
-//    maps from (2) and then multiplies the corresponding occurrences.
-//    If a string does not occur in a document, the product is zero.
-//    The function finally sums up all products.
-
-
-//def prod(lst1: List[String], lst2: List[String]) : Int = ..
-def prod(lst1: List[String], lst2: List[String]) : Int =
-    occurrences(lst1).map(x => occurrences(lst2).getOrElse(x._1, 0) * x._2).reduce(_ + _)
-
-//(4) Complete the functions overlap and similarity. The overlap of
-//    two documents is calculated by the formula given in the assignment
-//    description. The similarity of two strings is given by the overlap
-//    of the cleaned strings (see (1)).
-
-
-//def overlap(lst1: List[String], lst2: List[String]) : Double = ...
-def overlap(lst1: List[String], lst2: List[String]) : Double =
-    prod(lst1, lst2).toDouble/Math.max(prod(lst1, lst1).toDouble, prod(lst2, lst2).toDouble)
-//def similarity(s1: String, s2: String) : Double = ...
-def similarity(s1: String, s2: String) : Double =
-    overlap(clean(s1), clean(s2))
-
-
-/* Test cases
-import CW7a._
-val list1 = List("a", "b", "b", "c", "d")
-val list2 = List("d", "b", "d", "b", "d")
-occurrences(List("a", "b", "b", "c", "d"))
-occurrences(List("d", "b", "d", "b", "d"))
-prod(list1,list2) // 7
-overlap(list1, list2)   // 0.5384615384615384
-overlap(list2, list1)   // 0.5384615384615384
-overlap(list1, list1)   // 1.0
-overlap(list2, list2)   // 1.0
-// Plagiarism examples from
-// https://desales.libguides.com/avoidingplagiarism/examples
-val orig1 = """There is a strong market demand for eco-tourism in
-Australia. Its rich and diverse natural heritage ensures Australia's
-capacity to attract international ecotourists and gives Australia a
-comparative advantage in the highly competitive tourism industry."""
-val plag1 = """There is a high market demand for eco-tourism in
-Australia. Australia has a comparative advantage in the highly
-competitive tourism industry due to its rich and varied natural
-heritage which ensures Australia's capacity to attract international
-ecotourists."""
-similarity(orig1, plag1) // 0.8679245283018868
-// Plagiarism examples from
-// https://www.utc.edu/library/help/tutorials/plagiarism/examples-of-plagiarism.php
-val orig2 = """No oil spill is entirely benign. Depending on timing and
-location, even a relatively minor spill can cause significant harm to
-individual organisms and entire populations. Oil spills can cause
-impacts over a range of time scales, from days to years, or even
-decades for certain spills. Impacts are typically divided into acute
-(short-term) and chronic (long-term) effects. Both types are part of a
-complicated and often controversial equation that is addressed after
-an oil spill: ecosystem recovery."""
-val plag2 = """There is no such thing as a "good" oil spill. If the
-time and place are just right, even a small oil spill can cause damage
-to sensitive ecosystems. Further, spills can cause harm days, months,
-years, or even decades after they occur. Because of this, spills are
-usually broken into short-term (acute) and long-term (chronic)
-effects. Both of these types of harm must be addressed in ecosystem
-recovery: a controversial tactic that is often implemented immediately
-following an oil spill."""
-overlap(clean(orig2), clean(plag2))  // 0.728
-similarity(orig2, plag2)             // 0.728
-// The punchline: everything above 0.6 looks suspicious and
-// should be investigated by staff.
-*/
-
-}