I'm trying to use BinaryHeap and i found out that i cannot use foreach(). My question is, there is any other way to do it?, can i iterate a BinaryHeap?

Agustin:

> I'm trying to use BinaryHeap and i found out that i cannot use foreach(). My question is, there is any other way to do it?, can i iterate a BinaryHeap?

Please show the code :-)

Perhaps you need to look at the head, pop the head item, look at the head, etc.

Bye,
bearophile

On Thursday, 7 November 2013 at 09:00:11 UTC, bearophile wrote:
> Agustin:
>
>> I'm trying to use BinaryHeap and i found out that i cannot use foreach(). My question is, there is any other way to do it?, can i iterate a BinaryHeap?
>
> Please show the code :-)
>
> Perhaps you need to look at the head, pop the head item, look at the head, etc.
>
> Bye,
> bearophile

    BinaryHeap!(uint[]) heap;
    foreach(type; heap)
    {
     ....
    }

no property 'popFront' for type 'BinaryHeap!(uint[])'

On Thursday, 7 November 2013 at 12:14:22 UTC, Agustin wrote:
> On Thursday, 7 November 2013 at 09:00:11 UTC, bearophile wrote:
>> Agustin:
>>
>>> I'm trying to use BinaryHeap and i found out that i cannot use foreach(). My question is, there is any other way to do it?, can i iterate a BinaryHeap?
>>
>> Please show the code :-)
>>
>> Perhaps you need to look at the head, pop the head item, look at the head, etc.
>>
>> Bye,
>> bearophile
>
>     BinaryHeap!(uint[]) heap;
>     foreach(type; heap)
>     {
>      ....
>     }
>
> no property 'popFront' for type 'BinaryHeap!(uint[])'

It seems that i need to have a pointer to the underlying array.

    uint[] intArray;
    BinaryHeap!(uint[]) heap;
    heap.acquire(intArray);
    foreach(int; intArray)
    {
     ....
    }

Agustin:

> no property 'popFront' for type 'BinaryHeap!(uint[])'

Try to use front and removeFront (I don't know why there is removeFront instead of popFront).

Bye,
bearophile

On Thursday, 7 November 2013 at 12:29:44 UTC, bearophile wrote:
> Agustin:
>
>> no property 'popFront' for type 'BinaryHeap!(uint[])'
>
> Try to use front and removeFront (I don't know why there is removeFront instead of popFront).
>
> Bye,
> bearophile

Saddly i had to do this

    auto clone = _heap.dup;

    while (!clone.empty())
    {
        auto item = clone.front();
        // ... Do something with item
        clone.removeFront();
    }

Iterate directly over a binary heap will be better perfomance wise than doing that because i had to clone the heap to be able to iterate over without removing items from the original heap.

On Thursday, 7 November 2013 at 12:45:11 UTC, Agustin wrote:
> On Thursday, 7 November 2013 at 12:29:44 UTC, bearophile wrote:
>> Agustin:
>>
>>> no property 'popFront' for type 'BinaryHeap!(uint[])'
>>
>> Try to use front and removeFront (I don't know why there is removeFront instead of popFront).
>>
>> Bye,
>> bearophile
>
> Saddly i had to do this
>
>     auto clone = _heap.dup;
>
>     while (!clone.empty())
>     {
>         auto item = clone.front();
>         // ... Do something with item
>         clone.removeFront();
>     }
>
> Iterate directly over a binary heap will be better perfomance wise than doing that because i had to clone the heap to be able to iterate over without removing items from the original heap.

By looking at the source, having "private @property ref Store _store()" public will help a lot.

On Thursday, 7 November 2013 at 12:29:44 UTC, bearophile wrote:
> Agustin:
>
>> no property 'popFront' for type 'BinaryHeap!(uint[])'
>
> Try to use front and removeFront (I don't know why there is removeFront instead of popFront).
>
> Bye,
> bearophile

I had to implement a custom IterableBinaryHeap implementation.

http://pastebin.com/GeVAeCch

    IterableBinaryHeap!(Array!uint, "a < b") heap;
    heap.insert(0);
    heap.insert(3);
    heap.insert(2);
    heap.insert(1);
    foreach(item; heap)
        writeln(item);

On Thursday, 7 November 2013 at 14:31:27 UTC, Agustin wrote:
> On Thursday, 7 November 2013 at 12:29:44 UTC, bearophile wrote:
>> Agustin:
>>
>>> no property 'popFront' for type 'BinaryHeap!(uint[])'
>>
>> Try to use front and removeFront (I don't know why there is removeFront instead of popFront).
>>
>> Bye,
>> bearophile
>
> I had to implement a custom IterableBinaryHeap implementation.
>
> http://pastebin.com/GeVAeCch
>
>     IterableBinaryHeap!(Array!uint, "a < b") heap;
>     heap.insert(0);
>     heap.insert(3);
>     heap.insert(2);
>     heap.insert(1);
>     foreach(item; heap)
>         writeln(item);

The above code was working until i upgrade to DMD32 D Compiler v2.064.

Now i got:
  "Error: cannot uniquely infer foreach argument types"

Help!