final_stack_list

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

struct stack_n
{
    int number;
    struct stack_n *next;
};

struct list
{
    struct stack_n *stacks;
    struct list *next;
    struct list *prev;
};

int index ( struct list *ls )
{
    int i = 0;
    while (ls != NULL && ls->stacks != NULL)
    {
        ls = ls->next;
        i++;
    }
    return i;
}

struct list *find ( int ind, struct list **ls )
{
    int max_ind = index ( *ls ) - 1;
    if (ind > max_ind)
    {
        return NULL;
    }
    int to_back = max_ind - ind;
    while (to_back > 0)
    {
        *ls = (*ls)->next;
        to_back--;
    }
    struct list *tmp = *ls;
    while ((*ls)->prev != NULL)
        *ls = (*ls)->prev;
    return tmp;
}

int add (int ind, struct stack_n **top, struct list **ls )
{
    int max_ind = index ( *ls );
    if (ind > max_ind)
    {
        return 0;
    }

    struct list *p;
    p = *ls;
    *ls = (struct list *)malloc ( sizeof ( struct list ) );
    (*ls)->stacks = *top;
    (*ls)->next = p;
    (*ls)->prev = NULL;
    p->prev = *ls;

    if (ind != 0 && max_ind != ind)
    {
        struct list *tmp_p = find ( ind, ls );
        struct list *tmp_m = find ( ind - 1, ls );
        p->prev = NULL;
        tmp_m->prev = *ls;
        tmp_p->next = *ls;
        (*ls)->next = tmp_m;
        (*ls)->prev = tmp_p;

    }
    if (ind == 0 && max_ind != 0)
    {
        struct list *tmp = find ( 0, ls );
        (*ls)->prev = tmp;
        (*ls)->next = NULL;
        p->prev = NULL;
        tmp->next = *ls;
    }
    while ((*ls)->prev != NULL)
        *ls = (*ls)->prev;
    return 1;
}

bool sub ( int ind, struct list **ls )
{
    int max_ind = index ( *ls ) - 1;
    if (ind > max_ind)
    {
        return false;
    }
    struct list *p;
    int to_back = max_ind - ind;
    while (to_back > 0)
    {
        *ls = (*ls)->next;
        to_back--;
    }
    p = *ls;
    if (ind == 0 && max_ind == 0)
    {
        (*ls)->stacks = NULL;
        (*ls)->next = NULL;
        (*ls)->prev = NULL;
        return true;
    }
    if (ind == 0)
    {
        (*ls)->prev->next = NULL;
    }
    else if (ind == max_ind)
    {
        *ls = (*ls)->next;
        (*ls)->prev = NULL;
    }
    else
    {
        (*ls)->next->prev = (*ls)->prev;
        (*ls)->prev->next = (*ls)->next;
    }
    while ((*ls)->prev != NULL)
        *ls = (*ls)->prev;
    free ( p );

    return true;
}

void push ( int element, struct stack_n **top )
{
    struct stack_n *p;

    p = *top;
    *top = (struct stack_n *)malloc ( sizeof ( struct stack_n ) );
    (*top)->number = element;
    (*top)->next = p;
}

int pop ( struct stack_n **top )
{
    int element = INT_MAX;
    struct stack_n *p;

    if (*top != NULL)
    {
        p = *top;
        element = (*top)->number;
        *top = (*top)->next;
        free ( p );
    }
    return element;
}

void print ( struct list *ls )
{
    int max_ind = index ( ls );
    if (max_ind == 0)
    {
        printf ( "Empty!\n" );
    }
    else
    {
        int p;
        struct list *tmp_list;
        tmp_list = ls;
        while (max_ind--)
        {
            struct stack_n *tmp_stack;
            tmp_stack = ls->stacks;
            printf ( "L.%d --> ", max_ind );
            while (ls->stacks != NULL) {
                p = ls->stacks->number;
                printf ( "%d ", p );
                ls->stacks = ls->stacks->next;
            }
            ls->stacks = tmp_stack;
            printf ( "\n" );
            ls = ls->next;
        }
        ls = tmp_list;
        printf ( "----------------------------------------------||\n\n" );
    }
}

int main ( ) {

    struct stack_n *top = NULL;

    push ( 1, &top );
    push ( 2, &top );
    push ( 3, &top );


    struct stack_n *top2 = NULL;

    push ( 4, &top2 );
    push ( 5, &top2 );
    push ( 6, &top2 );


    struct list *ls = ( struct list * )malloc ( sizeof ( struct list ) );
    ls->stacks = NULL;
    ls->next = NULL;
    ls->prev = NULL;
    add ( 0, &top, &ls );
    add ( 1, &top2, &ls );

    struct stack_n *top4 = NULL;

    push ( 7, &top4 );
    push ( 8, &top4 );
    push ( 9, &top4 );
    add ( 1, &top4, &ls );
    struct list *top3 = find ( 1, &ls );
    print ( ls );
    sub ( 0, &ls );
    print ( ls );
    int s = index ( ls );
    print ( top3 );
    push ( 55, &(ls->stacks) );
    print ( ls );

    pop ( &(ls->stacks) );
    pop ( &(ls->stacks) );
    print ( ls );
    sub ( 1, &ls );
    sub ( 0, &ls );
    print ( ls );
    free ( ls );

    return 0;
}