Interesting Array Puzzle: Recursive children tallys?

[ultrus]

Hello,

I have an interesting puzzle. I have a list of places, with places that have parent places assigned to them in the same list. Example: North America and Colorado are in the same list, and North America is the parent of Colorado.

 

I have another list of locations/areas that are assigned to places in the places list. Example: "Coverage 3" is assigned to Colorado. I can easily run a function to tally up the locations in each place (see below), but that's the first step. The second step(s) is to get a total tally of each parent place including all the tallys of the children places. Ouch!@! Example: North Colorado has 2 total, Colorado has 1 total, and North America has 1 total to start. The Total of North America with children would be 4.

 

Here's what I have so far:

 

<?php
$places = array(
array("id"=>1, "name"=>"North America", "count"=>0, "parentID"=>0),
array("id"=>2, "name"=>"Colorado", "count"=>0, "parentID"=>1),
array("id"=>3, "name"=>"North Colorado", "count"=>0, "parentID"=>2)
);

$coverageAreas = array(
array("placeID"=>3, "name"=>"Coverage 1"),
array("placeID"=>3, "name"=>"Coverage 2"),
array("placeID"=>2, "name"=>"Coverage 3"),
array("placeID"=>1, "name"=>"Coverage 4"),
);

function getPlaceCountTotals() {
global $places, $coverageAreas;

//get direct place counts
for($i=0; $i<count($coverageAreas); $i++) {
	$for($p=0; $p<count($places); $p++) {
		if($coverageAreas[$i]["placeID"] == $places[$p]["id"]) {
			$places[$p]["count"]++;
                               break;
		}
	}
}

//?? ok, now how do I add children counts to parent counts??
//Example:

//Before:
//North America = 1
//Colorado = 1
//North Colorado = 2

//After:
//North America = 4
//Colorado = 3
//North Colorado = 2
}

getPlaceCountTotals();
?>

 

The above example is way simplified. In reality places are all over the place not in any particular order (at first anyway). Any thoughts on how to proceed? I don't need a full example, but any pointers to help get me over the hump would be greatly appreciated!

 

Thanks much in advance for the assist.

 

 

Edit:

Maybe if I can figure out the depth of each child, that would help...

[ultrus]

Ah I think I have it. Sometimes I just need to write things out and it makes more sense. I'll post something if it is worth while.

 

Thank you

[laffin]

I used something similar (w/o counting), to provide subcategories of unlimited depth to a download area. This way things could be very organized and looking them up would be simpler.

 

I used Thr Tree Based structure which u have.

than i built a cached index, so i wudnt have to keep rebuilding the tree.

 

since the counting is very important, ya may consider keeping a counter updated so ya dun have to build the tree in order to get a count as this will take the most amount of time.

 

Trees and Recursion, its a lot to take in, and at times may cause headaches, but it can be done.