Implement deadlock prevention logic and parallel Taylor series calculation #1
@@ -20,17 +20,18 @@ public class DeadlockPreventionWorkshop {
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}
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public static void useResources(Resource r1, Resource r2) {
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// TODO: Prevent deadlock by enforcing a consistent lock acquisition order
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// Hint: Compare resource IDs and always synchronize on the resource with the smaller ID first.
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// برای جلوگیری از ددلاک، بر اساس id منابع رو مرتب میکنیم تا همه تردها قفلها رو با یک ترتیب ثابت بگیرن
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Resource first = r1.getId() < r2.getId() ? r1 : r2;
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Resource second = r1.getId() < r2.getId() ? r2 : r1;
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System.out.println(Thread.currentThread().getName() + " is attempting to lock " + r1.getName());
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synchronized (r1) {
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System.out.println("+ " + Thread.currentThread().getName() + " locked " + r1.getName());
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System.out.println(Thread.currentThread().getName() + " is attempting to lock " + first.getName());
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synchronized (first) {
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System.out.println("+ " + Thread.currentThread().getName() + " locked " + first.getName());
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try { Thread.sleep(100); } catch (InterruptedException ignored) {}
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System.out.println(Thread.currentThread().getName() + " is attempting to lock " + r2.getName());
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synchronized (r2) {
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System.out.println("+ " + Thread.currentThread().getName() + " locked " + r2.getName());
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System.out.println(Thread.currentThread().getName() + " is attempting to lock " + second.getName());
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synchronized (second) {
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System.out.println("+ " + Thread.currentThread().getName() + " locked " + second.getName());
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System.out.println(Thread.currentThread().getName() + " using " + r1.getName() + " and " + r2.getName());
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}
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}
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@@ -6,15 +6,22 @@ import java.util.concurrent.locks.ReentrantLock;
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public class LockWorkshop {
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public static int counter = 0;
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// TODO: Create a ReentrantLock instance to protect the critical section
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// تعریف شیء قفل ReentrantLock برای محافظت از محدوده بحرانی
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private static final Lock lock = new ReentrantLock();
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public static class MyRunnable implements Runnable {
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@Override
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public void run() {
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int i;
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for (i = 0; i < 1_000_000; i++) {
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// TODO: Acquire the lock, increment the counter, and release the lock safely in a finally block
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counter += 1;
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// گرفتن قفل قبل از تغییر دادن مقدار کانتر مشترک
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lock.lock();
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try {
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counter += 1;
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} finally {
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// آزاد کردن قطعی قفل در بلوک finally برای امنیت بیشتر
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lock.unlock();
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}
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}
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System.out.println("Increments completed by " + Thread.currentThread().getName() + ": " + i);
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}
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@@ -3,15 +3,18 @@ package workshop.exercises;
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public class SynchronizedWorkshop {
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public static int counter = 0;
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// TODO: Define a lock object to prevent race condition
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// تعریف یک شیء قفل برای جلوگیری از تداخل دادهها در مانیتور اینتزینزیک
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private static final Object lock = new Object();
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public static class MyRunnable implements Runnable {
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@Override
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public void run() {
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int i;
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for (i = 0; i < 1_000_000; i++) {
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// TODO: Use a synchronized block to protect the counter increment
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counter += 1;
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// استفاده از بلوک synchronized روی شیء قفل برای محافظت از کانتر
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synchronized (lock) {
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counter += 1;
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}
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}
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System.out.println("Increments completed by " + Thread.currentThread().getName() + ": " + i);
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}
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@@ -21,14 +21,30 @@ public class TaylorSeries {
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@Override
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public void run() {
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// TODO: Calculate the n-th term of the Taylor series for sin(x):
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// term = (-1)^n * (x^(2n+1)) / (2n+1)!
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// Add the term to the global sum ensuring thread-safety.
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// محاسبه فرمول: term = (-1)^n * (x^(2n+1)) / (2n+1)!
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int exponent = 2 * n + 1;
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BigDecimal num = x.pow(exponent, mc);
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BigDecimal den = factorial(exponent);
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BigDecimal term = num.divide(den, mc);
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// اگه n فرد باشه جمله منفی میشه
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if (n % 2 == 1) {
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term = term.negate();
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}
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// اضافه کردن به sum سراسری به صورت ایمن و Thread-safe
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synchronized (TaylorSeries.class) {
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sum = sum.add(term, mc);
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}
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}
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// TODO: Implement factorial(k) using BigDecimal
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// پیادهسازی فاکتوریل با BigDecimal
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private BigDecimal factorial(int k) {
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return BigDecimal.ZERO;
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BigDecimal fact = BigDecimal.ONE;
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for (int i = 2; i <= k; i++) {
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fact = fact.multiply(BigDecimal.valueOf(i));
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}
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return fact;
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}
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}
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@@ -41,7 +57,8 @@ public class TaylorSeries {
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// Submit tasks to calculate terms
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for (int i = 0; i < 100; i++) {
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// TODO: Submit task to the thread pool
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// فرستادن تسکهای محاسبه به ترد پول
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threadPool.submit(new CalculateSin(x, i));
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}
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threadPool.shutdown();
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