#include <stdio.h>
#include <stdlib.h>
#define MAX_SIZE 100

typedef struct
{
    int start_block;
    int num_blocks;
} FileAllocation;

typedef struct node
{
    int block_index;
    struct node *next;
} BlockNode;

int disk[MAX_SIZE];
int disk_size = MAX_SIZE;
BlockNode *free_list = NULL;

void initializeDisk()
{
    int i;
    for (i = 0; i < disk_size; i++)
    {
        disk[i] = -1; // -1 indicates free space
    }
}

int allocateLinked(int num_blocks)
{
    if (free_list == NULL)
    {
        printf("Error: Disk is full.\n");
        return -1;
    }

    int start_block = free_list->block_index;
    BlockNode *current = free_list;
    int count = 0;
    while (current != NULL && count < num_blocks)
    {
        disk[current->block_index] = 1; // Mark block as allocated
        count++;
        current = current->next;
    }

    if (count < num_blocks)
    {
        printf("Error: Not enough free space.\n");
        return -1;
    }

    free_list = current; // Update free list
    return start_block;
}

void freeLinked(int start_block, int num_blocks)
{
    int i;
    for (i = start_block; i < start_block + num_blocks; i++)
    {
        disk[i] = -1; // Mark blocks as free
        BlockNode *new_node = (BlockNode *)malloc(sizeof(BlockNode));
        new_node->block_index = i;
        new_node->next = free_list;
        free_list = new_node; // Add to the beginning of free list
    }
}

void displayDisk()
{
    int i;
    printf("Disk Status:\n");
    for (i = 0; i < disk_size; i++)
    {
        printf("%d ", disk[i]);
    }
    printf("\n");
}

int main()
{
    initializeDisk();

    // Simulate free blocks in disk
    BlockNode *temp = NULL;
    int i;
    for (i = 0; i < disk_size; i += 5)
    {
        BlockNode *new_node = (BlockNode *)malloc(sizeof(BlockNode));
        new_node->block_index = i;
        new_node->next = temp;
        temp = new_node;
    }
    free_list = temp;

    int allocated_block = allocateLinked(7);
    if (allocated_block != -1)
    {
        printf("Linked allocation successful. Allocated block starting at index %d.\n", allocated_block);
    }
    displayDisk();

    // Free the allocated space
    freeLinked(allocated_block, 7);
    printf("Freed the allocated block.\n");
    displayDisk();

    return 0;
}