feat: Add SlackTimeScheduling new algorithm with Junit tests

Author: Hardvan

src/main/java/com/thealgorithms/scheduling/SlackTimeScheduling.java

@@ -0,0 +1,52 @@
+package com.thealgorithms.scheduling;
+
+import java.util.ArrayList;
+import java.util.Comparator;
+import java.util.List;
+
+/**
+ * SlackTimeScheduling is an algorithm that prioritizes tasks based on their
+ * slack time, which is defined as the difference between the task's deadline
+ * and the time required to execute it. Tasks with less slack time are prioritized.
+ *
+ * Use Case: Real-time systems with hard deadlines, such as robotics or embedded systems.
+ *
+ * @author Hardvan
+ */
+public class SlackTimeScheduling {
+
+    static class Task {
+        String name;
+        int executionTime;
+        int deadline;
+
+        Task(String name, int executionTime, int deadline) {
+            this.name = name;
+            this.executionTime = executionTime;
+            this.deadline = deadline;
+        }
+
+        int getSlackTime() {
+            return deadline - executionTime;
+        }
+    }
+
+    private final List<Task> tasks;
+
+    public SlackTimeScheduling() {
+        tasks = new ArrayList<>();
+    }
+
+    public void addTask(String name, int executionTime, int deadline) {
+        tasks.add(new Task(name, executionTime, deadline));
+    }
+
+    public List<String> scheduleTasks() {
+        tasks.sort(Comparator.comparingInt(Task::getSlackTime));
+        List<String> scheduledOrder = new ArrayList<>();
+        for (Task task : tasks) {
+            scheduledOrder.add(task.name);
+        }
+        return scheduledOrder;
+    }
+}

src/test/java/com/thealgorithms/scheduling/SlackTimeSchedulingTest.java

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+package com.thealgorithms.scheduling;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import java.util.List;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+
+public class SlackTimeSchedulingTest {
+
+    private SlackTimeScheduling scheduler;
+
+    @BeforeEach
+    public void setup() {
+        scheduler = new SlackTimeScheduling();
+    }
+
+    @Test
+    public void testAddAndScheduleSingleTask() {
+        scheduler.addTask("Task1", 2, 5);
+        List<String> expected = List.of("Task1");
+        assertEquals(expected, scheduler.scheduleTasks());
+    }
+
+    @Test
+    public void testScheduleMultipleTasks() {
+        scheduler.addTask("Task1", 2, 5);
+        scheduler.addTask("Task2", 1, 4);
+        scheduler.addTask("Task3", 3, 7);
+        List<String> expected = List.of("Task1", "Task2", "Task3");
+        assertEquals(expected, scheduler.scheduleTasks());
+    }
+
+    @Test
+    public void testScheduleTasksWithSameSlackTime() {
+        scheduler.addTask("Task1", 2, 5);
+        scheduler.addTask("Task2", 3, 6);
+        scheduler.addTask("Task3", 1, 4);
+        List<String> expected = List.of("Task1", "Task2", "Task3");
+        assertEquals(expected, scheduler.scheduleTasks());
+    }
+
+    @Test
+    public void testEmptyScheduler() {
+        List<String> expected = List.of();
+        assertEquals(expected, scheduler.scheduleTasks());
+    }
+}