I want to know what a de-queue is?
Is it same as a linked list?
If yes then,
Is it something like "de-queue can be represented as a linked list" ?
or
Is de-queue a "singly linked list" or "double linked list" (like alias to anyone of them)??
de-queue is Double-ended queue. In queue you have two basic operations:
1. Add element at the end of queue
2. Remove element from start of the queue.
de-queue supports total four basic operations:
1. Add element at start.
2. Remove element from start.
3. Add element at end.
4. Remove element from end.
Of course you can add other functionality like getting the value of first or last element without removing it etc.
You can implement de-queue using any data structure but efficient implementations are done using dyanmic array or doubly linked list. For more details follow this link http://en.wikipedia.org/wiki/Double-ended_queue
Related
I have this Shortcut which queries a Notion database, then fetches the IDs and titles of pages from the database and turns them into key : value pairs.
I want to add those key : value pairs to the dictionary shown at the top of the screenshot. The problem is, even though I can see that I'm adding to the dictionary inside the Repeat With Each Item loop -
When I check the contents of my Categories dictionary at the end of the Shortcut, those entries haven't been saved.
I have seen this answer, which appears to solve the same problem. But when I implement it and then check the contents of the variable inside the loop, nothing is even being set here.
I'd be very grateful for any pointers here.
I figured out the problem - I needed to set the dictionary as a variable outside the loop -
And then I can update the dictionary inside the loop -
I don't know why that works but it does ¯\(ツ)/¯
I see it's only possible to iterate based on the result set from a previous step; that being so, I guess there's no way to add to that result set within the for each loop?
I'm using for each, as I need concurrency
Any ideas?
As far as I know, it's difficult to add to a set/array inside for each loop. If you want to add item to the array, you just need to use union() method. For example, I have a array like this:
And I want to add item(s) as below screenshot to the array.
Now we just need to do it like this:
The expression is: union(variables('arr'), variables('addItems'))
I am trying to make a lighting system in Game Maker and to structure the system I want to contain all of the lights in a ds_map. I want that ds_map to be held inside a second ds_map that contains all of the lights in the system
lights {
"l-01": {"x":20, "y":40, "radius":15},
...
}
The question I have regards cleaning up the system:
Do I have to iterate through the map destroying all of the sub-maps and then destroy the map, will Game Maker automatically destroy the sub-maps when the light map gets destroyed?
ds_map_destroy(lights); // do the sub maps ("l-01") also get destroyed?
or do I have to do it like this:
var k = ds_map_find_first(lights);
repeat(ds_map_size(lights)){
ds_map_destroy(lights[? k]);
k = ds_map_find_next(lights, k);
}
Following along with the first question, if I delete a key will game maker destroy the sub-map
ds_map_delete(lights, "l-01") // will this destroy the map indexed under "l-01"
You may ask: "Why are you using a ds_map to hold a bunch of ds_maps, why not just create a list of maps?
The answer comes from the second question. If I held the maps in a list, and I need to delete one of the maps the list will resize on removal of the map, therefore offsetting all of the other indexed values
The second reason is that in Game Maker, ds_maps are much quicker than ds_lists
I hope I have made my question clear and that one of you out there has the answer.
If you marked added data structure as list/map (using ds_list_mark_as_map() or ds_list_mark_as_list() or ds_map_add_list() or ds_map_add_map()) then it will be deleted automatically. Otherwise you need delete it yourself.
From documentation about ds_list_mark_as_list():
NOTE: Once a ds_list has had a value within it flagged as another list or map, destroying the list will also destroy the marked lists and maps too. This means that you do not have to manually go through the list contents and destroy the marked data structures individually before destroying the "parent" list.
and ds_map_add_list():
If a ds_map has a list added in this way, destroying the parent map will also destroy the contained lists and free their memory.
If you have doubts you can check, is data structure exists or not, using ds_exists()
I have the below code in my web site.
I want to track each anchor tag using DTM. I know how to track single element. Since here we have a bunch of different elements, can anyone help how to track them using DTM? I don't want to create separate rule for each element. In a single rule how can we track these elements.
Here is an example of what you can do.
For Element Tag or Selector put "a.at-share-btn" (no quotes). This will target all the relevant links first. We can look for this too in the next step, but "pre-qualifying" it with this will improve performance so that the rule is not evaluated against every single a click.
Then, under Rule Conditions, add a Criteria of type Data > Custom.
In the Custom box, add the following:
var shareType = this.getAttribute('class').match(/\bat-svc-([a-z_-]+)/i);
if (shareType&&shareType[1]) {
_satellite.setVar('shareType',shareType[1]);
return true;
}
return false;
This code looks for the class (e.g. "at-svc-facebook") and puts the last part of it (e.g. "facebook") into a data element named shareType.
Then, you can reference it using %shareType% in any of the DTM fields. Note: because this data element is made on-the-fly, it will not show up in the auto-complete when you type it out in a field.
Alternatively, in custom code boxes (e.g. if you are needing to reference it in a javascript/3rd party tag box), you can use _satellite.getVar('shareType')
i have a problem in JavaFX Binding, I have two observable Lists one of them is static, so when i bind them using (Bindings.bindcontentbidirectional), the two lists get empty and i checked by printing their size and the console shows before binding "List 1 = 3" "List 2 = 0" and after the Bind command the two lists size is ZERO!,so what is the problem??, another question, does it matter in a bidirectional bind who comes in the first parameter???
Yes, the order of the parameters does matter. When creating the Binding, the first list will be cleared and filled with the content of the second list. After this point, they will be synchronized bidirectionally as long as the Binding exists.
Assuming you did something like Bindings.bindContentBidirectional(list1, list2), your first list has been cleared upon creating the Binding because list2 was empty at that point. So everything went as to be expected.