#include <stdio.h>
#include <stdlib.h>
#include <pthread.h>

#define NUM_THREADS 4  // Number of threads (should be even)
#define ARRAY_SIZE 8   // Size of the array

int array[ARRAY_SIZE];
pthread_barrier_t barrier;

// Function to swap two array elements
void swap(int *a, int *b) {
    int temp = *a;
    *a = *b;
    *b = temp;
}

// Function executed by each thread
void *sort(void *arg) {
    int thread_part = *(int*)arg;
    for (int phase = 0; phase < ARRAY_SIZE; phase++) {
        // Determine pairs for this phase
        int index = thread_part * 2 + (phase % 2);

        // Compare and swap if needed
        if (index < ARRAY_SIZE - 1 && array[index] > array[index + 1]) {
            swap(&array[index], &array[index + 1]);
        }

        // Wait for all threads to finish this phase
        pthread_barrier_wait(&barrier);
    }

    pthread_exit(NULL);
}

int main() {
    pthread_t threads[NUM_THREADS];
    int thread_args[NUM_THREADS];
    int status;

    // Initialize array with random values
    for (int i = 0; i < ARRAY_SIZE; i++) {
        array[i] = rand() % 100;  // Random numbers between 0 and 99
    }

    // Initialize barrier
    pthread_barrier_init(&barrier, NULL, NUM_THREADS);

    // Create threads for sorting
    for (int i = 0; i < NUM_THREADS; i++) {
        thread_args[i] = i;
        status = pthread_create(&threads[i], NULL, sort, (void *)&thread_args[i]);

        if (status != 0) {
            printf("ERROR; return code from pthread_create() is %d\n", status);
            exit(-1);
        }
    }

    // Wait for all threads to complete
    for (int i = 0; i < NUM_THREADS; i++) {
        pthread_join(threads[i], NULL);
    }

    // Print the sorted array
    printf("Sorted Array: ");
    for (int i = 0; i < ARRAY_SIZE; i++) {
        printf("%d ", array[i]);
    }
    printf("\n");

    // Clean up and exit
    pthread_barrier_destroy(&barrier);

    return 0;
}