2020-11-01 Update: Added "Sum without highest and lowest number" and "Count of positives / sum of negatives"

Author: fartem

src/main/java/com/smlnskgmail/jaman/codewarsjava/kyu8/CountOfPositivesSumOfNegatives.java

@@ -0,0 +1,32 @@
+package com.smlnskgmail.jaman.codewarsjava.kyu8;
+
+import java.util.stream.IntStream;
+
+// https://www.codewars.com/kata/576bb71bbbcf0951d5000044
+public class CountOfPositivesSumOfNegatives {
+
+    private final int[] input;
+
+    public CountOfPositivesSumOfNegatives(int[] input) {
+        this.input = input;
+    }
+
+    public int[] solution() {
+        if (input == null) {
+            return new int[]{};
+        }
+        int positivesCount = (int) IntStream
+                .of(input)
+                .filter(value -> value > 0)
+                .count();
+        int negativesSum = IntStream
+                .of(input)
+                .filter(value -> value < 0)
+                .sum();
+        if (positivesCount == 0 && negativesSum == 0) {
+            return new int[]{};
+        }
+        return new int[] { positivesCount, negativesSum };
+    }
+
+}

src/main/java/com/smlnskgmail/jaman/codewarsjava/kyu8/SumWithoutHighestAndLowestNumber.java

@@ -0,0 +1,30 @@
+package com.smlnskgmail.jaman.codewarsjava.kyu8;
+
+import java.util.Arrays;
+
+// https://www.codewars.com/kata/576b93db1129fcf2200001e6
+public class SumWithoutHighestAndLowestNumber {
+
+    private final int[] input;
+
+    public SumWithoutHighestAndLowestNumber(int[] input) {
+        this.input = input;
+    }
+
+    public int solution() {
+        if (input == null || input.length < 2) {
+            return 0;
+        }
+        final int[] minimumValue = { Integer.MAX_VALUE };
+        final int[] maximumValue = { Integer.MIN_VALUE };
+        return Arrays.stream(input).peek(operand -> {
+            if (operand > maximumValue[0]) {
+                maximumValue[0] = operand;
+            }
+            if (operand < minimumValue[0]) {
+                minimumValue[0] = operand;
+            }
+        }).sum() - minimumValue[0] - maximumValue[0];
+    }
+
+}

src/test/java/com/smlnskgmail/jaman/codewarsjava/kyu8/CountOfPositivesSumOfNegativesTest.java

@@ -0,0 +1,29 @@
+package com.smlnskgmail.jaman.codewarsjava.kyu8;
+
+import org.junit.Test;
+
+import static org.junit.Assert.assertArrayEquals;
+
+public class CountOfPositivesSumOfNegativesTest {
+
+    @Test
+    public void countPositivesSumNegatives_BasicTest() {
+        assertArrayEquals(
+                new int[] { 10, -65 },
+                new CountOfPositivesSumOfNegatives(
+                        new int[] { 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, -11, -12, -13, -14, -15 }
+                ).solution()
+        );
+    }
+
+    @Test
+    public void countPositivesSumNegatives_InputWithZeroes() {
+        assertArrayEquals(
+                new int[] { 8, -50 },
+                new CountOfPositivesSumOfNegatives(
+                        new int[] { 0, 2, 3, 0, 5, 6, 7, 8, 9, 10, -11, -12, -13, -14 }
+                ).solution()
+        );
+    }
+
+}

src/test/java/com/smlnskgmail/jaman/codewarsjava/kyu8/SumWithoutHighestAndLowestNumberTest.java

@@ -0,0 +1,17 @@
+package com.smlnskgmail.jaman.codewarsjava.kyu8;
+
+import org.junit.Test;
+
+import static org.junit.Assert.assertEquals;
+
+public class SumWithoutHighestAndLowestNumberTest {
+
+    @Test
+    public void BasicTests() {
+        assertEquals(
+                16,
+                new SumWithoutHighestAndLowestNumber(new int[] { 6, 2, 1, 8, 10 }).solution()
+        );
+    }
+
+}