How to match and relate data unique? - php

Question

I'm having some difficulties figuring out how to return the best unique match, while assigning as many as possible.
Scenario: Each kid has a list of favorite fruits with a personal score. We only have ONE of each fruit, so we want to give it to the kid with the highest preference. One can be left without fruit if someone has a higher score, but we still want to give out as many fruits as possible.
The expected result would be:
0 = [1] Apple
1 = [0] Mango
2 = [0] Banana
3 = null
This is my input array:
Array
(
[0] => Array
(
[0] => Array
(
[name] => Banana
[score] => 80.2
)
[1] => Array
(
[name] => Apple
[score] => 40
)
)
[1] => Array
(
[0] => Array
(
[name] => Mango
[score] => 70
)
[1] => Array
(
[name] => Banana
[score] => 40
)
)
[2] => Array
(
[0] => Array
(
[name] => Banana
[score] => 90
)
[1] => Array
(
[name] => Orange
[score] => 20
)
)
[3] => Array
(
[0] => Array
(
[name] => Mango
[score] => 60
)
)
)

Answer 1

My approach first flattens your input into a simple 2D array allowing all rows to be sorted by score while preserving the fruit and childid data. After sorting, all rows are iterated (versus doing iterated full-array searches) and only stores the most preferred fruit, if available, for each child as requested.
OP's Input:
$input=[
[['name'=>'Banana','score'=>80.2],['name'=>'Apple','score'=>40]],
[['name'=>'Mango','score'=>70],['name'=>'Banana','score'=>40]],
[['name'=>'Banana','score'=>90],['name'=>'Orange','score'=>20]],
[['name'=>'Mango','score'=>60]]
];
Method:
$result=array_fill_keys(array_keys($input),null); // list all child ids and default to null
// flatten input array for simple sorting and iteration
foreach($input as $i=>$subarrays){
foreach($subarrays as $a){
$restructured[]=['score'=>$a['score'],'fruit'=>$a['name'],'childid'=>$i];
}
}
rsort($restructured); // will sort the array by score DESC
foreach($restructured as $a){
if(is_null($result[$a['childid']]) && !in_array($a['fruit'],$result)){
// only "fruitless" children wanting what is available
$result[$a['childid']]=$a['fruit'];
}
}
var_export($result);
Output:
array (
0 => 'Apple',
1 => 'Mango',
2 => 'Banana',
3 => NULL,
)