From a74512e23183b7b81747fd5b5c84a8b826547a0c Mon Sep 17 00:00:00 2001
From: Kirill Timofeev <kirill.timofeev@waveaccess.global>
Date: Wed, 29 Nov 2023 14:29:46 +0300
Subject: [PATCH] init

---
 src/main/Main.java | 109 +++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 109 insertions(+)
 create mode 100644 src/main/Main.java

diff --git a/src/main/Main.java b/src/main/Main.java
new file mode 100644
index 0000000..e23da7e
--- /dev/null
+++ b/src/main/Main.java
@@ -0,0 +1,109 @@
+import java.util.Random;
+import java.util.concurrent.BlockingQueue;
+import java.util.concurrent.LinkedBlockingQueue;
+import java.util.concurrent.Semaphore;
+
+record Homework(String content, int timeLimit) {
+}
+
+class Student implements Runnable {
+    private final String name;
+    private final BlockingQueue<Homework> queue;
+
+    public Student(String name, BlockingQueue<Homework> queue) {
+        this.name = name;
+        this.queue = queue;
+    }
+
+    public void submitHomework(Homework homework) throws InterruptedException {
+        queue.put(homework);
+        System.out.println(name + " submitted " + homework.content() + " homework");
+    }
+
+    @Override
+    public void run() {
+        Random random = new Random();
+
+        while (true) {
+            Homework homework = new Homework(
+                    "Task " + (random.nextInt(10000) + 1),
+                    random.nextInt(9001) + 1000
+            );
+
+            try {
+                submitHomework(homework);
+                Thread.sleep(random.nextInt(3000) + 1000);
+            } catch (InterruptedException e) {
+                e.printStackTrace();
+            }
+        }
+    }
+}
+
+class Grader implements Runnable {
+    private final String name;
+    private final BlockingQueue<Homework> queue;
+    private final Semaphore semaphore;
+
+    public Grader(String name, BlockingQueue<Homework> queue, Semaphore semaphore) {
+        this.name = name;
+        this.queue = queue;
+        this.semaphore = semaphore;
+    }
+
+    @Override
+    public void run() {
+        while (true) {
+            try {
+                semaphore.acquire();
+                Homework homework = queue.poll();
+
+                if (homework != null) {
+                    gradeHomework(homework);
+                }
+
+                semaphore.release();
+            } catch (InterruptedException e) {
+                e.printStackTrace();
+            }
+        }
+    }
+
+    private void gradeHomework(Homework homework) throws InterruptedException {
+        Thread.sleep(10);
+        System.out.println(name + " is grading " + homework.content() + " homework from student");
+        // Simulate grading process
+        Thread.sleep(2000);
+        System.out.println(name + " finished grading " + homework.content() + " homework");
+    }
+}
+
+class HomeworkSystem {
+    public final BlockingQueue<Homework> homeworkQueue;
+    private final Semaphore gradingSemaphore;
+
+    public HomeworkSystem() {
+        this.homeworkQueue = new LinkedBlockingQueue<>();
+        this.gradingSemaphore = new Semaphore(3);
+    }
+
+    public void startGraders(int numGraders) {
+        for (int i = 1; i <= numGraders; i++) {
+            Grader grader = new Grader("Grader " + i, homeworkQueue, gradingSemaphore);
+            new Thread(grader).start();
+        }
+    }
+}
+
+public class Main {
+    public static void main(String[] args) {
+        HomeworkSystem homeworkSystem = new HomeworkSystem();
+        homeworkSystem.startGraders(3);
+
+        Student student1 = new Student("1", homeworkSystem.homeworkQueue);
+        Student student2 = new Student("2", homeworkSystem.homeworkQueue);
+
+        new Thread(student1).start();
+        new Thread(student2).start();
+    }
+}
\ No newline at end of file