Add JobSchedulingWithDeadline algorithm (#5608)

Author: Hardvan

DIRECTORY.md

@@ -475,6 +475,7 @@
           * scheduling
             * [FCFSScheduling](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/scheduling/FCFSScheduling.java)
             * [HighestResponseRatioNextScheduling](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/scheduling/HighestResponseRatioNextScheduling.java)
+            * [JobSchedulingWithDeadline](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/scheduling/JobSchedulingWithDeadline.java)
             * [MLFQScheduler](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/scheduling/MLFQScheduler.java)
             * [PreemptivePriorityScheduling](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/scheduling/PreemptivePriorityScheduling.java)
             * [RRScheduling](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/scheduling/RRScheduling.java)
@@ -963,6 +964,7 @@
           * scheduling
             * [FCFSSchedulingTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/scheduling/FCFSSchedulingTest.java)
             * [HighestResponseRatioNextSchedulingTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/scheduling/HighestResponseRatioNextSchedulingTest.java)
+            * [JobSchedulingWithDeadlineTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/scheduling/JobSchedulingWithDeadlineTest.java)
             * [MLFQSchedulerTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/scheduling/MLFQSchedulerTest.java)
             * [PreemptivePrioritySchedulingTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/scheduling/PreemptivePrioritySchedulingTest.java)
             * [RRSchedulingTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/scheduling/RRSchedulingTest.java)

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

@@ -0,0 +1,88 @@
+package com.thealgorithms.scheduling;
+
+import java.util.Arrays;
+import java.util.Comparator;
+
+/**
+ * A class that implements a job scheduling algorithm to maximize profit
+ * while adhering to job deadlines and arrival times.
+ *
+ * This class provides functionality to schedule jobs based on their profit,
+ * arrival time, and deadlines to ensure that the maximum number of jobs is completed
+ * within the given timeframe. It sorts the jobs in decreasing order of profit
+ * and attempts to assign them to the latest possible time slots.
+ */
+public final class JobSchedulingWithDeadline {
+    private JobSchedulingWithDeadline() {
+    }
+
+    /**
+     * Represents a job with an ID, arrival time, deadline, and profit.
+     *
+     * Each job has a unique identifier, an arrival time (when it becomes available for scheduling),
+     * a deadline by which it must be completed, and a profit associated with completing the job.
+     */
+    static class Job {
+        int jobId;
+        int arrivalTime;
+        int deadline;
+        int profit;
+
+        /**
+         * Constructs a Job instance with the specified job ID, arrival time, deadline, and profit.
+         *
+         * @param jobId      Unique identifier for the job
+         * @param arrivalTime Time when the job becomes available for scheduling
+         * @param deadline   Deadline for completing the job
+         * @param profit     Profit earned upon completing the job
+         */
+        Job(int jobId, int arrivalTime, int deadline, int profit) {
+            this.jobId = jobId;
+            this.arrivalTime = arrivalTime;
+            this.deadline = deadline;
+            this.profit = profit;
+        }
+    }
+
+    /**
+     * Schedules jobs to maximize profit while respecting their deadlines and arrival times.
+     *
+     * This method sorts the jobs in descending order of profit and attempts
+     * to allocate them to time slots that are before or on their deadlines,
+     * provided they have arrived. The function returns an array where the first element
+     * is the total number of jobs scheduled and the second element is the total profit earned.
+     *
+     * @param jobs An array of Job objects, each representing a job with an ID, arrival time,
+     *             deadline, and profit.
+     * @return An array of two integers: the first element is the count of jobs
+     *         that were successfully scheduled, and the second element is the
+     *         total profit earned from those jobs.
+     */
+    public static int[] jobSequencingWithDeadlines(Job[] jobs) {
+        Arrays.sort(jobs, Comparator.comparingInt(job -> - job.profit));
+
+        int maxDeadline = Arrays.stream(jobs).mapToInt(job -> job.deadline).max().orElse(0);
+
+        int[] timeSlots = new int[maxDeadline];
+        Arrays.fill(timeSlots, -1);
+
+        int count = 0;
+        int maxProfit = 0;
+
+        // Schedule the jobs
+        for (Job job : jobs) {
+            if (job.arrivalTime <= job.deadline) {
+                for (int i = Math.min(job.deadline - 1, maxDeadline - 1); i >= job.arrivalTime - 1; i--) {
+                    if (timeSlots[i] == -1) {
+                        timeSlots[i] = job.jobId;
+                        count++;
+                        maxProfit += job.profit;
+                        break;
+                    }
+                }
+            }
+        }
+
+        return new int[] {count, maxProfit};
+    }
+}

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

@@ -0,0 +1,43 @@
+package com.thealgorithms.scheduling;
+
+import static org.junit.jupiter.api.Assertions.assertArrayEquals;
+
+import org.junit.jupiter.api.Test;
+
+class JobSchedulingWithDeadlineTest {
+
+    @Test
+    void testJobSequencingWithDeadlines1() {
+        JobSchedulingWithDeadline.Job[] jobs = {new JobSchedulingWithDeadline.Job(1, 1, 4, 20), new JobSchedulingWithDeadline.Job(2, 1, 1, 10), new JobSchedulingWithDeadline.Job(3, 1, 1, 40), new JobSchedulingWithDeadline.Job(4, 1, 1, 30)};
+        int[] result = JobSchedulingWithDeadline.jobSequencingWithDeadlines(jobs);
+        assertArrayEquals(new int[] {2, 60}, result); // Expected output: 2 jobs, 60 profit
+    }
+
+    @Test
+    void testJobSequencingWithDeadlines2() {
+        JobSchedulingWithDeadline.Job[] jobs = {new JobSchedulingWithDeadline.Job(1, 1, 2, 100), new JobSchedulingWithDeadline.Job(2, 1, 1, 19), new JobSchedulingWithDeadline.Job(3, 1, 2, 27), new JobSchedulingWithDeadline.Job(4, 1, 1, 25), new JobSchedulingWithDeadline.Job(5, 1, 1, 15)};
+        int[] result = JobSchedulingWithDeadline.jobSequencingWithDeadlines(jobs);
+        assertArrayEquals(new int[] {2, 127}, result); // Expected output: 2 jobs, 127 profit
+    }
+
+    @Test
+    void testJobSequencingWithDeadlinesWithArrivalTimes() {
+        JobSchedulingWithDeadline.Job[] jobs = {new JobSchedulingWithDeadline.Job(1, 2, 5, 50), new JobSchedulingWithDeadline.Job(2, 3, 4, 60), new JobSchedulingWithDeadline.Job(3, 1, 3, 20)};
+        int[] result = JobSchedulingWithDeadline.jobSequencingWithDeadlines(jobs);
+        assertArrayEquals(new int[] {3, 130}, result); // All 3 jobs fit within their deadlines
+    }
+
+    @Test
+    void testJobSequencingWithDeadlinesNoJobs() {
+        JobSchedulingWithDeadline.Job[] jobs = {};
+        int[] result = JobSchedulingWithDeadline.jobSequencingWithDeadlines(jobs);
+        assertArrayEquals(new int[] {0, 0}, result); // No jobs, 0 profit
+    }
+
+    @Test
+    void testJobSequencingWithDeadlinesSingleJob() {
+        JobSchedulingWithDeadline.Job[] jobs = {new JobSchedulingWithDeadline.Job(1, 1, 1, 50)};
+        int[] result = JobSchedulingWithDeadline.jobSequencingWithDeadlines(jobs);
+        assertArrayEquals(new int[] {1, 50}, result); // 1 job scheduled, 50 profit
+    }
+}