Online PHP editor | refs for kBkS7

<?php $d = [ [1,2,3,4,5], [1,6,7,8,9], [1,5,6,10,11], [6,12,13,14,15] ]; $set = []; foreach($d as $idx => $val){ foreach($val as $v){ $set[ $v ][ $idx ] = true; } } $removedNumbers = []; foreach($d as $idx => $val){ $commonElements = 0; foreach($val as $v){ if(count($set[ $v ]) > 1){ $commonElements++; unset($set[ $v ][ $idx ]); } } if($commonElements > 1){ unset($d[ $idx ]); $removedNumbers = array_merge($removedNumbers, $val); } } print_r($removedNumbers); print_r($d);