import java.util.concurrent.locks.Lock;
import java.util.concurrent.locks.ReentrantLock;
import java.util.concurrent.locks.ReentrantReadWriteLock;

public class ReadersWritersProblem {
    // Shared data by readers and writers
    private static int sharedData = 0;

    // Lock for reader-writer access
    private static final ReentrantReadWriteLock readWriteLock = new ReentrantReadWriteLock();
    private static final Lock readLock = readWriteLock.readLock();
    private static final Lock writeLock = readWriteLock.writeLock();

    static class Reader implements Runnable {
        @Override
        public void run() {
            for (int i = 0; i < 5; i++) {
                readLock.lock();
                try {
                    System.out.println(Thread.currentThread().getName() + " reads: " + sharedData);
                    Thread.sleep(100); // Simulate read operation
                } catch (InterruptedException e) {
                    Thread.currentThread().interrupt();
                } finally {
                    readLock.unlock();
                }
            }
        }
    }

    static class Writer implements Runnable {
        @Override
        public void run() {
            for (int i = 0; i < 5; i++) {
                writeLock.lock();
                try {
                    sharedData++;
                    System.out.println(Thread.currentThread().getName() + " writes: " + sharedData);
                    Thread.sleep(100); // Simulate write operation
                } catch (InterruptedException e) {
                    Thread.currentThread().interrupt();
                } finally {
                    writeLock.unlock();
                }
            }
        }
    }

    public static void main(String[] args) {
        // Creating reader and writer threads
        Thread reader1 = new Thread(new Reader(), "Reader 1");
        Thread reader2 = new Thread(new Reader(), "Reader 2");
        Thread writer1 = new Thread(new Writer(), "Writer 1");
        Thread writer2 = new Thread(new Writer(), "Writer 2");

        // Start threads
        reader1.start();
        reader2.start();
        writer1.start();
        writer2.start();
    }
}