// Preliminary Part about Code Similarity+ −
//========================================+ −
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object CW7a { + −
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//(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.+ −
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//def clean(s: String) : List[String] = ...+ −
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//(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.+ −
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//def occurrences(xs: List[String]): Map[String, Int] = ..+ −
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//(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. + −
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//def prod(lst1: List[String], lst2: List[String]) : Int = ..+ −
+ −
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//(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 similarity(s1: String, s2: String) : Double = ...+ −
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/* Test cases+ −
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val list1 = List("a", "b", "b", "c", "d") + −
val list2 = List("d", "b", "d", "b", "d")+ −
+ −
occurrences(List("a", "b", "b", "c", "d")) // Map(a -> 1, b -> 2, c -> 1, d -> 1)+ −
occurrences(List("d", "b", "d", "b", "d")) // Map(d -> 3, b -> 2)+ −
+ −
prod(list1,list2) // 7 + −
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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+ −
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// The punchline: everything above 0.6 looks suspicious and + −
// should be investigated by staff.+ −
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*/+ −
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}+ −