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

struct dll_node
{
    int data;
    struct  dll_node *prev , *next;
};

struct dll_node *create_list(int data)
{
    struct dll_node *new_node=(struct dll_node *)
        malloc(sizeof(struct dll_node));
        if(NULL!=new_node)
        {
            new_node->data=data;
            new_node->prev=new_node->next=new_node;
        }
        return new_node;
};

struct dll_node *find_max_node(struct dll_node *node)
{
    struct dll_node *start=node, *result=node;
    int maximum=node->data;
    do
    {
        if(maximum<node->data)
        {
            maximum=node->data;
            result=node;
        }
        node = node->next;
    }while(node!=start);
    return result;
};

struct dll_node *find_next_node(struct dll_node *node, int data)
{
    node=find_max_node(node);
    struct dll_node *start = node;
    do
    {
        if(node->data < data)
            break;
        node=node->next;
    }while (node!=start);
    return node;
};

void insert_node(struct dll_node *node, int data)
{
    if(NULL == node)
        return;

    struct dll_node *new_node=(struct dll_node *)
        malloc(sizeof(struct dll_node));
        if(NULL!=new_node)
        {
            new_node->data=data;
            node=find_next_node(node,data);
            new_node->next=node;
            new_node->prev=node->prev;
            node->prev->next=new_node;
            node->prev=new_node;
        }
}

struct dll_node *delete_node(struct dll_node *node, int data)
{
    if(NULL==node)
        return NULL;

    node = find_next_node(node,data);
    node-node->prev;
    if(node->data==data)
    {
        if(node==node->next)
        {
            free(node);
            return NULL;
        }
        else
        {
            struct dll_node *next = node->next;
            node->prev->next=node->next;
            node->next->prev=node->prev;
            free(node);
            node=next;
        }
    }
    return node;
};

void print_list(struct dll_node *node)
{
    if(NULL==node)
        return;

    node=find_max_node(node);
    struct dll_node *start = node;
    do
    {
        printf("%d",node->data);
        node=node->next;
    }while(node!=start);
    printf("\n");
}

void remove_list(struct dll_node **node)
{
    if(NULL==*node)
        return;

    struct dll_node *start = *node;
    do
    {
        struct dll_node *next=(*node)->next;
        free(*node);
        *node=next;
    }while(*node!=start);
    *node=NULL;
}

int main()
{
    struct dll_node *dlcl=create_list(1);
    int i;

    for(i=2;i<5;i++)
        insert_node(dlcl,i);
    for(i=6;i<10;i++)
        insert_node(dlcl,i);
        printf("List elements:\n");
        print_list(dlcl);
}