Create linked list from elements of a Binary tree at a certain depth

Question

I am trying to build a linked list, with the elements at a certain depth

I came up with this:

void nivel(ABin a, int k, SList *l, int level){
    if (!a) return;
    if(k == level){
     SList n = (SList)malloc(sizeof(struct slist));
     n->value = a->value;
     n->next=(*l);
     (*l) = n;
     return;
    }else{
        nivel(a->left, k, l, level+1);
        nivel(a->right, k, l, level+1);
    }
}

It does work

But the exercise asks to use this header: SList nivel (ABin a, int n)

I have tried with a void to practice. But can't figure out how to make the one that returns the linked lists.

Data from structure and binary tree:

typedef struct slist
{
    int value;
    struct slist* next;
} *SList;

typedef struct arvbin* ABin;
typedef struct arvbin
{
    int value;
    ABin right;
    ABin left;
} arvb;

EDIT:

<---------------working with header in the exercise-----------> // A thank you to Politank-Z

SList nivel_(ABin a, int k){
    SList *l; 

    nivel(a, k, l, 1);

    return l;
}


void nivel(ABin a, int k, SList *l, int level){
    if (!a) return;
    if(k == level){
     SList n = (SList)malloc(sizeof(struct slist));
     n->value = a->value;
     n->next=(*l);
     (*l) = n;
     return;
    }else{
        nivel(a->left, k, l, level+1);
        nivel(a->right, k, l, level+1);
    }
}

I'm really sorry, i tested it again, and it did work... But i am finding it rather difficult to use the header from the exercise — skills
– skills, Commented Jul 8, 2015 at 2:46
How so? Have you tried calling your function from a function defined by the prototype? — Politank-Z
– Politank-Z, Commented Jul 8, 2015 at 2:47
What's the goal of nivel? Given a binary tree, output some form of linked list from it? — Caleb An
– Caleb An, Commented Jul 8, 2015 at 2:54

Politank-Z · Accepted Answer · 2015-07-08 13:33:50Z

1

Regarding your difficulty with the prototype: it is fairly common to be restricted to a function prototype which doesn't meet the needs of your implementation. In such cases, it is often easier to call your function from the prototyped function then to shoehorn your functionality into the prototype.

answered Jul 8, 2015 at 13:33

Politank-Z

3,7433 gold badges27 silver badges28 bronze badges

Sign up to request clarification or add additional context in comments.

Comments

henry_dew · Accepted Answer · 2015-07-08 02:48:22Z

1

Do you mean that you want to build a linked list using binary tree? However, you may add a new item into your list when (k == level), then you call nivel(a->left, k, l, level+1). It won't add any node here, because k != level+1 now, so your list will contain just one node actually...

BTW, you should ensure nivel add one node into your list everytime.

answered Jul 8, 2015 at 2:48

henry_dew

112 bronze badges

1 Comment

skills Over a year ago

Actually, the code works fine. At each recursive folding, it does check for that branch if the level is the pretended one, and it does create a linked list with the elements from that level. The problem was not that, but to use the header given in the exercise

Caleb An · Accepted Answer · 2015-07-08 02:56:44Z

0

} *SList;

will create a pointer type called SList. This causes confusion within your code, because you use SList *l which is a pointer to a pointer! Change your struct typedef to just } SList. This way you don't have to dereference a pointer of a pointer to reach the pointer value.

edited Jul 8, 2015 at 2:56

answered Jul 8, 2015 at 2:49

Caleb An

3661 silver badge10 bronze badges

Collectives™ on Stack Overflow

Create linked list from elements of a Binary tree at a certain depth

3 Answers 3

Comments

1 Comment

Comments

Your Answer

Linked

Hot Network Questions

Collectives™ on Stack Overflow

3 Answers 3

Comments

1 Comment

Comments

Your Answer

Sign up or log in

Post as a guest

Linked

Related