Adapt optimal C++/ JavaScript solution

Reviewed-on: #3

src/nativeMain/kotlin/space.dezentrale.prgrnd/SumOfTwo.kt

@@ -0,0 +1,25 @@
+package space.dezentrale.prgrnd
+
+class SumOfTwo {
+    fun simpleSolution(nums: IntArray, target: Int): IntArray {
+        nums.forEachIndexed { idxA, numA ->
+            nums.forEachIndexed { idxB, numB ->
+                if (idxA != idxB && numA + numB == target) {
+                    return intArrayOf(idxA, idxB)
+                }
+            }
+        }
+        return intArrayOf(-1, -1)
+    }
+
+    fun optimalSolution(nums: IntArray, target: Int): IntArray {
+        val numsToIndices = nums.mapIndexed { index: Int, num: Int -> num to index }.toMap()
+        println("numsToIndices = $numsToIndices")
+        for ((index, num) in nums.withIndex()) {
+            if (numsToIndices.containsValue(target - num)) {
+                return intArrayOf(numsToIndices[target - num]!!, index)
+            }
+        }
+        return intArrayOf(-1, -1)
+    }
+}

src/nativeTest/kotlin/space/dezentrale/prgrnd/DuplicatesTest.kt

@@ -4,7 +4,7 @@ import kotlin.test.Test
 import kotlin.test.assertFalse
 import kotlin.test.assertTrue
 
-class ContainsDuplicateTest {
+class DuplicatesTest {
     @Test
     fun `it returns true for '1_2_3_1'`() {
         assertTrue(containsDuplicate(intArrayOf(1, 2, 3, 1)))

src/nativeTest/kotlin/space/dezentrale/prgrnd/SumOfTwoTest.kt

@@ -0,0 +1,60 @@
+package space.dezentrale.prgrnd
+
+import kotlin.test.Test
+import kotlin.test.assertContentEquals
+
+class SumOfTwoTest {
+    @Test
+    fun `simpleSolution returns an array with 0 and 1 for 2_7_11_15 and 9`() {
+        val sumOfTwo = SumOfTwo()
+
+        val twoSum = sumOfTwo.simpleSolution(intArrayOf(2, 7, 11, 15), 9)
+
+        assertContentEquals(twoSum, intArrayOf(0, 1))
+    }
+
+    @Test
+    fun `simpleSolution returns an array with 1 and 2 for 3_2_4 and 6`() {
+        val sumOfTwo = SumOfTwo()
+
+        val twoSum = sumOfTwo.simpleSolution(intArrayOf(3, 2, 4), 6)
+
+        assertContentEquals(twoSum, intArrayOf(1, 2))
+    }
+
+    @Test
+    fun `simpleSolution returns an array with 0 and 1 for 3_3 and 6`() {
+        val sumOfTwo = SumOfTwo()
+
+        val twoSum = sumOfTwo.simpleSolution(intArrayOf(3, 3), 6)
+
+        assertContentEquals(twoSum, intArrayOf(0, 1))
+    }
+
+    @Test
+    fun `optimalSolution returns an array with 0 and 1 for 2_7_11_15 and 9`() {
+        val sumOfTwo = SumOfTwo()
+
+        val twoSum = sumOfTwo.optimalSolution(intArrayOf(2, 7, 11, 15), 9)
+
+        assertContentEquals(twoSum, intArrayOf(0, 1))
+    }
+
+    @Test
+    fun `optimalSolution returns an array with 1 and 2 for 3_2_4 and 6`() {
+        val sumOfTwo = SumOfTwo()
+
+        val twoSum = sumOfTwo.optimalSolution(intArrayOf(3, 2, 4), 6)
+
+        assertContentEquals(twoSum, intArrayOf(1, 2))
+    }
+
+    @Test
+    fun `optimalSolution returns an array with 0 and 1 for 3_3 and 6`() {
+        val sumOfTwo = SumOfTwo()
+
+        val twoSum = sumOfTwo.optimalSolution(intArrayOf(3, 3), 6)
+
+        assertContentEquals(twoSum, intArrayOf(0, 1))
+    }
+}