3v4l.org

run code in 200+ php & hhvm versions
Bugs & Features
<?php class CategoryTree { protected $roots = []; public function addCategory($category, $parent) { if ($this->categoryExists($this->roots, $category)) { throw new InvalidArgumentException("Category: '$category' already exists."); } if ($parent === null) { $this->roots[$category] = []; return; } $node = &$this->findNode($parent, $this->roots); if(!isset($node)) { throw new InvalidArgumentException("Parent node: '$parent' not found."); } $node[$category] = []; } public function getChildren($parent) { $node = $this->findNode($parent, $this->roots); if(!isset($node)) { throw new InvalidArgumentException("Parent node: '$parent' not found."); } return array_keys($node); } protected function &findNode($node, &$root) { if (in_array($node, array_keys($root))) { return $root[$node]; } foreach ($root as $n) { return $this->findNode($node, $n); } } protected function categoryExists($nodes, $category) { $exists = false; foreach($nodes as $key => $node) { if ($key === $category) { return true; } $exists = $this->categoryExists($node, $category); } return $exists; } } // For testing purposes (do not submit uncommented): $c = new CategoryTree; $c->addCategory('A', null); $c->addCategory('B', 'A'); $c->addCategory('A', 'B'); $c->addCategory('C', 'A'); echo implode(',', $c->getChildren('A'));
based on 24HNi
Output for 7.0.0 - 7.2.0
Fatal error: Uncaught InvalidArgumentException: Category: 'A' already exists. in /in/F98Lj:9 Stack trace: #0 /in/F98Lj(58): CategoryTree->addCategory('A', 'B') #1 {main} thrown in /in/F98Lj on line 9
Process exited with code 255.
Output for 5.4.10 - 5.6.28
Fatal error: Uncaught exception 'InvalidArgumentException' with message 'Category: 'A' already exists.' in /in/F98Lj:9 Stack trace: #0 /in/F98Lj(58): CategoryTree->addCategory('A', 'B') #1 {main} thrown in /in/F98Lj on line 9
Process exited with code 255.
Output for 5.3.20 - 5.3.29
Parse error: syntax error, unexpected '[' in /in/F98Lj on line 4
Process exited with code 255.