Online PHP editor | output for ACvJa

<?php $sequences = ["6", "66", "67", "68", "69", "697", "698", "699"]; $data = ["69212345", "6209876544", "697986546"]; function get_longest_subsequence_element(array $sequences, $str){ $sequenceTree = []; $longestSequence = ""; $strLength = strlen($str); $sequences = array_filter($sequences, function($v)use($strLength){ return strlen($v) <= $strLength; }); $sequenceTree = create_sequence_tree($sequences); $longestSequence = search_sequence_tree($sequenceTree, $str, $longestSequence); return $longestSequence; } function create_sequence_tree(array $sequences){ $sequenceTree = []; foreach($sequences as $sequence){ $parts = str_split($sequence); $ref = &$sequenceTree; while($key = array_shift($parts)) $ref = &$ref[$key]; unset($ref); } return $sequenceTree; } function search_sequence_tree(array $sequenceTree, $str, &$longestSequence, &$sequenceTmp = ""){ foreach($sequenceTree as $v => $checkValue){ if(strpos($str, $sequenceTmp . $v) !== FALSE){ $sequenceTmp .= $v; if(strlen($sequenceTmp) > strlen($longestSequence)) $longestSequence = $sequenceTmp; if(!is_null($sequenceTree[$v])) search_sequence_tree($sequenceTree[$v], $str, $longestSequence, $sequenceTmp); else $sequenceTmp = substr($sequenceTmp, 0 ,-1); } } return $longestSequence; } foreach($data as $str) { echo get_longest_subsequence_element($sequences, $str) . "<br>"; } ?>