Finished exercise 7

README.md

@@ -1,16 +1 @@
-# Kotlin Programming Language Course - Faculty of Sciences, Novi Sad
-
-Welcome to the Kotlin Programming Language Course at the Faculty of Sciences, Novi Sad!
-
-## Project Overview
-
-This project contains a set of exercises designed to help you learn Kotlin programming concepts. Each exercise is provided with instructions and corresponding Kotlin files where you can implement your solutions.
-
-## How to Load Project from GitHub in IntelliJ IDEA
-
-### 1. Clone the Repository
-
-- Open IntelliJ IDEA.
-- Go to `File` > `New` > `Project from Version Control` > `Git`.
-- In the `URL` field, enter the URL of the GitHub repository: https://github.com/vuksa/kotlin-programming-language-course.git
-- Click `Clone` to clone the repository to your local machine.
+bojan ludajic

build.gradle.kts

@@ -11,6 +11,7 @@ repositories {
 
 dependencies {
     testImplementation(kotlin("test"))
+    testImplementation("junit:junit:4.13")
     testImplementation("org.junit.jupiter:junit-jupiter-params:5.8.1")
 }
 

src/main/kotlin/common/FileReader.kt

@@ -0,0 +1,22 @@
+package common
+
+import java.nio.file.Path
+import java.nio.file.Paths
+import kotlin.io.path.readLines
+import kotlin.io.path.toPath
+
+object FileReader {
+    /**
+     * Reads the contents of a file located at the specified path.
+     *
+     * @param path The path of the file to read.
+     * @return A list of strings representing the lines of the file.
+     * @throws NullPointerException if the resource at the specified path is null.
+     */
+    fun readFileInResources(path: String): List<String> {
+        val normalizedPath = path.takeIf { it.startsWith("/") } ?: "/$path"
+        return requireNotNull(this.javaClass.getResource(normalizedPath.toString())?.toURI()?.toPath()) {
+            "Unresolved path."
+        }.readLines()
+    }
+}

src/main/kotlin/exercise2/task1/FindPairOfHighestSum.kt

@@ -18,7 +18,10 @@ import org.jetbrains.exercise2.task3.findPairWithBiggestDifference
  */
 
 internal fun List<Int>.findHighestSumPair(): Pair<Int, Int> {
-    TODO("Implement me!!")
+    val prvi = this.sorted().get(this.lastIndex)
+    val drugi = this.sorted().get(this.lastIndex-1)
+
+    return Pair(prvi, drugi)
 }
 
 fun main() {

src/main/kotlin/exercise2/task2/FindPairOfHighestSumFunctional.kt

@@ -20,7 +20,9 @@ import org.jetbrains.exercise2.task3.findPairWithBiggestDifference
  */
 
 internal fun List<Int>.findHighestSumPairFunctional(): Pair<Int, Int> {
-    TODO("Implement me!!")
+    return Pair(
+        this.sorted().get(this.lastIndex), this.sorted().get(this.lastIndex-1)
+    )
 }
 
 fun main() {

src/main/kotlin/exercise2/task3/ConvertMethodToFunctionalApproach.kt

@@ -17,24 +17,29 @@ import kotlin.math.abs
  */
 
 internal fun List<Int>.findPairWithBiggestDifference(): Pair<Int, Int> {
-    // TODO refactor me to functional approach and make tests pass!!!
-    var resultPair: Pair<Int, Int>? = null
-    var biggestDifference = Int.MIN_VALUE
-
-    for (i in this.indices) {
-        for (j in (i + 1) until this.size) {
-            val first = this[i]
-            val second = this[j]
-            val absDifference = abs(first - second)
-
-            if (absDifference >= biggestDifference) {
-                biggestDifference = absDifference
-                resultPair = Pair(first, second)
-            }
-        }
-    }
 
-    return resultPair!!
+    return Pair(
+        this.sorted().get(this.size-1), this.sorted().get(0)
+    )
+
+
+//    var resultPair: Pair<Int, Int>? = null
+//    var biggestDifference = Int.MIN_VALUE
+//
+//    for (i in this.indices) {
+//        for (j in (i + 1) until this.size) {
+//            val first = this[i]
+//            val second = this[j]
+//            val absDifference = abs(first - second)
+//
+//            if (absDifference >= biggestDifference) {
+//                biggestDifference = absDifference
+//                resultPair = Pair(first, second)
+//            }
+//        }
+//    }
+//
+//    return resultPair!!
 }
 
 fun main() {

src/main/kotlin/exercise2/task4/ProcessCountriesData.kt

@@ -59,27 +59,35 @@ internal val countries = listOf(
  */
 
 internal fun List<Country>.findCountryWithBiggestTotalArea(): Country {
-    TODO("Implement me!!!")
+    return countries.maxBy { it.totalAreaInSquareKilometers }
 }
 
 internal fun List<Country>.findCountryWithBiggestPopulation(): Country {
-    TODO("Implement me!!!")
+   return countries.maxBy { it.population }
 }
 
 internal fun List<Country>.findCountryWithHighestPopulationDensity(): Country {
-    TODO("Implement me!!!")
+    return countries.maxBy {
+        it.population/it.totalAreaInSquareKilometers
+    }
 }
 
 internal fun List<Country>.findCountryWithLowestPopulationDensity(): Country {
-    TODO("Implement me!!!")
+    return countries.minBy {
+        it.population/it.totalAreaInSquareKilometers
+    }
 }
 
 internal fun List<Country>.findLanguageSpokenInMostCountries(): String {
-    TODO("Implement me!!!")
+    return countries.flatMap { it.languages }
+        .groupingBy { it }
+        .eachCount()
+        .maxBy { it.value }
+        .key
 }
 
 internal fun List<Country>.filterCountriesThatSpeakLanguage(language: String): List<Country> {
-    TODO("Implement me!!!")
+    return countries.filter { country -> country.languages.contains(language) }
 }
 
 
@@ -88,7 +96,7 @@ fun main() {
     println("Country with a biggest population is a ${countries.findCountryWithBiggestPopulation().name}")
     println("Country with a biggest population density is a ${countries.findCountryWithHighestPopulationDensity().name}")
     println("Country with a lowest population density is a ${countries.findCountryWithLowestPopulationDensity().name}")
-    println("Language spoken in most countries is a ${countries.findLanguageSpokenInMostCountries()}")
+    println("Language spoken in most countries is ${countries.findLanguageSpokenInMostCountries()}")
     val countriesThatSpeakEnglish = countries.filterCountriesThatSpeakLanguage("English")
     println("Countries that speak English language are ${countriesThatSpeakEnglish.joinToString { it.name }}")
 }

src/main/kotlin/exercise2/task5/CreateUserDSL.kt

@@ -49,11 +49,15 @@ internal data class Address(
  */
 
 internal fun user(initUser: User.() -> Unit): User {
-    TODO("Implement me!!!")
+    val user = User()
+    return user.apply(initUser)
 }
 
-internal fun User.address(initAddress: Address.() -> Unit): User {
-    TODO("Implement me!!!")
+internal fun User.address   (initAddress: Address.() -> Unit): User {
+    val adr = Address()
+    adr.initAddress()
+    this.address = adr
+    return this
 }
 
 fun main() {

src/main/kotlin/exercise3/task1/BalancedBrackets.kt

@@ -1,4 +1,5 @@
 package exercise3.task1
+import java.util.Stack
 
 /**
  * Task1: Balanced Brackets (Parentheses) Problem
@@ -26,9 +27,32 @@ package exercise3.task1
 
 
 internal fun isExpressionBalanced(expression: String): Boolean {
-    TODO("Implement me!!!")
+    val chars = Stack<Char>()
+    val opening = "({["
+    val closing = ")}]"
+
+    for(char in expression) {
+        when {
+           char in opening -> chars.add(char)
+           char in closing -> {
+               if(chars.isEmpty() || !valid(chars.lastElement(), char)) {
+                   return false
+               }
+               chars.removeLast()
+           }
+        }
+    }
+    return chars.isEmpty()
 }
 
+fun valid(opening: Char, closing: Char): Boolean {
+    return (opening == '(' && closing == ')') ||
+            (opening == '[' && closing == ']') ||
+            (opening == '{' && closing == '}')
+}
+
+
+
 fun main() {
     val expressions = listOf(
         "{[()]}" to true,