如何获得多维数组的多个交叉点？

Question

Initial:

Array
(
    [0] => Array
        (
            [0] => a
            [1] => b
        )

    [1] => Array
        (
            [0] => a
            [1] => c
        )

    [2] => Array
        (
            [0] => c
            [1] => b
        )
    [3] => Array
        (
            [0] => d
            [1] => e
        )        
)

Result:

Array
(
    [0] => Array
        (
            [0] => a
            [1] => b
            [2] => c
        )
    [1] => Array
        (
            [0] => d
            [1] => e
        )        
)

The first three items of initial array are related to each other but last one not. I think it can be solved by using Floyd-Warshall Algoritm. Please help me to get result.

Answer 1

No idea what floyd-warshall algorhitm is, and not sure about your optimatization needs, but I made this:

$array = array(
   ['a', 'b'],
   ['a', 'c'],
   ['c', 'b'],
   ['d', 'e']
);

$result = array();
foreach($array as $itemOriginal){ //passing every array from the original array
   $passed = false;

   foreach($result as &$itemResult){ //passing every array from the new array (empty in the start)
      foreach($itemOriginal as $item){ //passing every item from original arrays
         if(in_array($item, $itemResult)){ //checking if the item is in one of earlier passed array transfered into new array already
            $itemResult = array_unique(array_merge($itemResult,  $itemOriginal)); //merging items into new array if one of their items equals
            $passed = true; //no need to check another item from the current original array
            break;
         }
      }

      if($passed == true) //no need to find any of original items in new array
         break;
   }

   if($passed == false) //for case the none of checked original items are in new array
      $result[] = $itemOriginal;
}

echo '<pre>';
print_r($result); //to check it