Finished excercises 1 and 2 (Aleksa Martinović)

src/main/kotlin/exercise1/task1/GradeCalculator.kt

@@ -40,13 +40,25 @@ import java.util.Scanner
  */
 
 internal fun calculateGrade(score: Int): Int {
-    TODO("Implement me!!!")
+//    require(score in 0..100) {
+//        "Score is out of range 0-100!"
+//    }
+    return when {
+        score in 0..50 -> 5
+        score in 51..60 -> 6
+        score in 61..70 -> 7
+        score in 71..80 -> 8
+        score in 81..90 -> 9
+        score in 91..100 -> 10
+        else -> throw IllegalArgumentException("Score out of range 0-100")
+    }
 }
 
 fun main() {
     print("Enter student score: ")
     val scanner = Scanner(System.`in`)
     val score = scanner.nextInt()
-
-    calculateGrade(score)
+    val grade = calculateGrade(score)
+    val msg = if(grade != 5) "Student's grade is: $grade" else "Student didn't pass the exam"
+    println(msg)
 }

src/main/kotlin/exercise1/task2/PrintPyramid.kt

@@ -57,7 +57,14 @@ package org.jetbrains.exercise1.task2
  */
 
 internal fun printPyramid(level: Int) {
-    TODO("Implement me!!!")
+    require (level in 3..15) {
+        "Level is out of range"
+    }
+    for(i in 1..level) {
+        val spaces = " ".repeat(level - i)
+        val stars = "*".repeat(2 * i - 1)
+        println("$spaces$stars$spaces")
+    }
 }
 
 fun main() {

src/main/kotlin/exercise1/task3/ScrabbleWordScoreCalculator.kt

@@ -31,8 +31,18 @@ package org.jetbrains.exercise1.task3
  *
  */
 
+val charMap = mapOf(
+    'A' to 1, 'E' to 1, 'I' to 1, 'O' to 1, 'U' to 1, 'L' to 1, 'N' to 1, 'R' to 1, 'S' to 1, 'T' to 1,
+    'D' to 2, 'G' to 2,
+    'B' to 3, 'C' to 3, 'M' to 3, 'P' to 3,
+    'F' to 4, 'H' to 4, 'V' to 4, 'W' to 4, 'Y' to 4,
+    'K' to 5,
+    'J' to 8, 'X' to 8,
+    'Q' to 10, 'Z' to 10,
+)
+
 internal fun calculateWordScrabbleScore(word: String): Int {
-    TODO("Implement me!!!")
+    return word.sumOf { charMap.getOrDefault(it.uppercaseChar(), 0) }
 }
 
 fun main() {

src/main/kotlin/exercise1/task4/PalindromeNumber.kt

@@ -28,11 +28,19 @@ package org.jetbrains.exercise1.task4
  */
 
 internal fun isPalindrome(x: Int): Boolean {
-    TODO("Implement me!!!")
+    require(x in -1000000..1000000) {
+        "Number must be in range -1000000..1000000"
+    }
+    return when {
+        x < 0 -> false
+        x.toString().length == 1 -> true
+        x.toString() == x.toString().reversed() -> true
+        else -> false
+    }
 }
 
 fun main() {
-    val number = 121
+    val number = 56465
     if (isPalindrome(number)) {
         println("Number $number is a palindrome.")
     } else {

src/main/kotlin/exercise1/task5/ReverseInteger.kt

@@ -1,5 +1,7 @@
 package org.jetbrains.exercise1.task5
 
+import kotlin.math.abs
+
 /**
  * Task 5: Given an integer x, return x with its digits reversed.
  *
@@ -27,10 +29,10 @@ package org.jetbrains.exercise1.task5
  */
 
 internal fun reverseInteger(x: Int): Int {
-    TODO("Implement me!!!")
+    require(x in -1000000..1000000) { "Number must be integer in range -1000000..1000000" }
+    return if (x < 0) ("-" + abs(x).toString().reversed()).toInt() else x.toString().reversed().toInt()
 }
-
 fun main() {
-    val integer = -321
+    val integer = -78952
     println("Reverse integer of number $integer is ${reverseInteger(integer)}")
 }

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

@@ -1,5 +1,6 @@
 package exercise2.task1
 
+import exercise2.task2.findHighestSumPairFunctional
 import org.jetbrains.exercise2.common.isEqualsTo
 import org.jetbrains.exercise2.task3.findPairWithBiggestDifference
 
@@ -18,7 +19,20 @@ import org.jetbrains.exercise2.task3.findPairWithBiggestDifference
  */
 
 internal fun List<Int>.findHighestSumPair(): Pair<Int, Int> {
-    TODO("Implement me!!")
+    require(this.size >= 2) { "List must have at least two integers." }
+    require(this.all { it in -1000..1000 })
+    var maxSum = Integer.MIN_VALUE
+    var pair: Pair<Int, Int>? = null
+    for((index, item) in this.dropLast(1).withIndex()) {
+        for(j in (index + 1) until this.size) {
+            val sum = item + this[j]
+            if(sum >= maxSum) {
+                maxSum = sum
+                pair = Pair(item, this[j])
+            }
+        }
+    }
+    return pair!!
 }
 
 fun main() {

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

@@ -1,5 +1,6 @@
 package exercise2.task2
 
+import exercise2.task1.findHighestSumPair
 import org.jetbrains.exercise2.common.isEqualsTo
 import org.jetbrains.exercise2.task3.findPairWithBiggestDifference
 
@@ -20,7 +21,9 @@ import org.jetbrains.exercise2.task3.findPairWithBiggestDifference
  */
 
 internal fun List<Int>.findHighestSumPairFunctional(): Pair<Int, Int> {
-    TODO("Implement me!!")
+    require(this.size >= 2) { "List must have at least two integers." }
+    require(this.all { it in -1000..1000 })
+    return this.sortedDescending().let { sortedList -> sortedList.first() to sortedList[1] }
 }
 
 fun main() {

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

@@ -1,5 +1,6 @@
 package org.jetbrains.exercise2.task3
 
+import exercise2.task2.findHighestSumPairFunctional
 import org.jetbrains.exercise2.common.isEqualsTo
 import kotlin.math.abs
 
@@ -17,24 +18,26 @@ 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!!
+//    STANDARD WAY:
+//    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)
+//            }
+//        }
+//    }
+//
+//  FUNCTIONAL APPROACH:
+    require(this.size >= 2) { "List must have at least two integers." }
+    return this.sortedDescending().let { sortedList -> sortedList.first() to sortedList.last() }
 }
 
 fun main() {

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

@@ -59,27 +59,33 @@ internal val countries = listOf(
  */
 
 internal fun List<Country>.findCountryWithBiggestTotalArea(): Country {
-    TODO("Implement me!!!")
+    return this.maxBy { it.totalAreaInSquareKilometers }
 }
 
 internal fun List<Country>.findCountryWithBiggestPopulation(): Country {
-    TODO("Implement me!!!")
+    return this.maxBy { it.population }
 }
 
 internal fun List<Country>.findCountryWithHighestPopulationDensity(): Country {
-    TODO("Implement me!!!")
+    return this.maxBy { it.population / it.totalAreaInSquareKilometers }
 }
 
 internal fun List<Country>.findCountryWithLowestPopulationDensity(): Country {
-    TODO("Implement me!!!")
+    return this.minBy { it.population / it.totalAreaInSquareKilometers }
 }
 
 internal fun List<Country>.findLanguageSpokenInMostCountries(): String {
-    TODO("Implement me!!!")
+    return this.flatMap { it.languages }
+        .groupingBy { it }
+        .eachCount()
+        .toList()
+        .sortedByDescending { it.second }
+        .map{ it -> it.first }
+        .first()
 }
 
 internal fun List<Country>.filterCountriesThatSpeakLanguage(language: String): List<Country> {
-    TODO("Implement me!!!")
+    return this.filter { it.languages.contains(language) }
 }
 
 
@@ -91,4 +97,5 @@ fun main() {
     println("Language spoken in most countries is a ${countries.findLanguageSpokenInMostCountries()}")
     val countriesThatSpeakEnglish = countries.filterCountriesThatSpeakLanguage("English")
     println("Countries that speak English language are ${countriesThatSpeakEnglish.joinToString { it.name }}")
+    //println(countries.flatMap { it.languages }.groupingBy { it }.eachCount().toList().sortedByDescending { it.second }.map{ it -> it.first }.first())
 }

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

@@ -49,11 +49,16 @@ internal data class Address(
  */
 
 internal fun user(initUser: User.() -> Unit): User {
-    TODO("Implement me!!!")
+    val user = User()
+    user.initUser()
+    return user
 }
 
 internal fun User.address(initAddress: Address.() -> Unit): User {
-    TODO("Implement me!!!")
+    val address = Address()
+    address.initAddress()
+    this.address = address
+    return this
 }
 
 fun main() {