特点:
- 一次加载所有数据 array(id, pid), array(id, pid)
- 通过一次循环构建树型结构
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/** * Class BTree * @package j\tree\tests * @property array $tree */ class BTree { protected $source; public $index = []; public $idKey = 'id'; public $pidKey = 'pid'; public $childKey = 'child'; /** * BTree constructor. * @param $source */ public function __construct($source){ $this->source = $source; } public function __get($name){ if($name == 'tree'){ return $this->tree = $this->buildTree(); } else { return null; } } protected function buildTree(){ $keyId = $this->idKey; $keyPid = $this->pidKey; $keyChild = $this->childKey; $tree = array(); $childMap =& $this->index; foreach($this->source as $item) { $item[$keyChild] = array(); //给每个节点附加一个child项 $key = $item[$keyId]; if($item[$keyPid] == 0) { if(isset($childMap[$key])){ // 已设置当前子类映射 $childMap[$key] += $item; $tree[$key] =& $childMap[$key]; } else { $tree[$key] = $item; $childMap[$key] =& $tree[$key]; } }else { $pid = $item[$keyPid]; if(isset($childMap[$key])){ // 已设置当前子类映射 $childMap[$key] += $item; $childMap[$pid][$keyChild][$key] =& $childMap[$key]; } else { $childMap[$pid][$keyChild][$key] = $item; $childMap[$key] =& $childMap[$pid][$keyChild][$key]; } } } return $tree; } function getTree(){ return $this->tree; } /** * @param $id * @return array */ function getParent($id){ return $this->index[$id]; } function getParents($id, $self = false, $maxLevel = 6) { $keyId = $this->idKey; $keyPid = $this->pidKey; $item = $this->index[$id]; $parents = $self ? [$id => $item] : []; $i = 0; while(isset($this->index[$item[$keyPid]])){ $item = $parents[$item[$keyId]] = $this->index[$item[$keyPid]]; if($i++ > $maxLevel){ break; } } return array_reverse($parents, true); } function getParentIds($id, $self = false, $maxLevel = 6){ return array_keys($this->getParents($id, $self, $maxLevel)); } function parentId($id){ return $this->index[$id][$this->pidKey]; } /** * @param $id * @return array */ function getChild($id){ return $this->index[$id][$this->childKey]; } function getChildIdentifying($id, $self = false, $recursive = true){ $ids = $self ? [$id] : array(); $items = $this->index[$id][$this->childKey]; if($recursive){ while($item = array_pop($items)){ $ids[] = $item[$this->idKey]; if(count($item[$this->childKey]) > 0){ foreach($item[$this->childKey] as $_item){ array_push($items, $_item); } } } } else { $ids = array_merge($ids, array_keys($items[$this->childKey])); } return $ids; // array_walk_recursive($this->tree[$id]['child'], function($item, $key) use(& $ids){ // if($key == 'id'){ // $ids[] = $item; // } // }); } }; // b+树 // 测试数据 $data = array( array('id' => 1, 'pid' => 0), array('id' => 4, 'pid' => 2), array('id' => 3, 'pid' => 2), array('id' => 2, 'pid' => 1), ); $t = new BTree($data); $tree = $t->getTree(); assert_expr(count($tree) == 1, 'ROOT NODE TEST'); assert_expr(count($tree[1]['child']) == 1, 'Child test1'); assert_expr(count($tree[1]['child'][2]['child']) == 2, 'Child test1'); assert_expr(count($t->getChildIdentifying(1)) == 3, 'Child ids'); assert_expr(count($t->getChildIdentifying(2)) == 2, 'Child ids'); assert_expr(count($t->getChildIdentifying(3)) == 0, 'Child ids'); assert_expr(count($t->getChildIdentifying(4)) == 0, 'Child ids'); |