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  1. <?php
  2. error_reporting(-1);
  3.  
  4. class Tree
  5. {
  6.     const FORMAT_TEXT = 0;
  7.     const FORMAT_HTML = 1;
  8.  
  9.     protected $rootIds;
  10.  
  11.     protected $template;
  12.  
  13.     /** @var array Template, indexed by nodes ids */
  14.     protected $nodes;
  15.  
  16.     protected $adjacencyList;
  17.  
  18.  
  19.     public function __construct($template)
  20.     {
  21.         $this->setTemplate($template);
  22.     }
  23.  
  24.     public function setTemplate($template)
  25.     {
  26.         $this->template = $template;
  27.         $this->nodes = $this->getNodes($template);
  28.         $this->rootIds = $this->getRootIds($template);
  29.         $this->adjacencyList = $this->buildAdjacencyList($template);
  30.     }
  31.  
  32.     public function format($format)
  33.     {
  34.         $output = '';
  35.  
  36.         foreach ($this->rootIds as $rootId) {
  37.             $this->walkTree($this->nodes[$rootId], $output, $format);
  38.         }
  39.  
  40.         return $output;
  41.     }
  42.  
  43.     public function __toString()
  44.     {
  45.         $this->format(static::FORMAT_TEXT);
  46.     }
  47.  
  48.     protected function buildAdjacencyList($template)
  49.     {
  50.         $adjacencyList = [];
  51.  
  52.         foreach ($template as $node) {
  53.             if ($node['parentId'] !== null) {
  54.                 if (isset($adjacencyList[$node['parentId']])) {
  55.                     $adjacencyList[$node['parentId']][] = $node['id'];
  56.                 } else {
  57.                     $adjacencyList[$node['parentId']] = [$node['id']];
  58.                 }
  59.             }
  60.         }
  61.  
  62.         return $adjacencyList;
  63.     }
  64.  
  65.     protected function getNodes($template)
  66.     {
  67.         $nodes = [];
  68.  
  69.         foreach ($template as $node) {
  70.             $nodes[$node['id']] = $node;
  71.         }
  72.  
  73.         return $nodes;
  74.     }
  75.  
  76.     protected function getRootIds($template)
  77.     {
  78.         $rootIds = [];
  79.  
  80.         foreach ($template as $node) {
  81.             if ($node['parentId'] === null) {
  82.                 $rootIds[] = $node['id'];
  83.             }
  84.         }
  85.  
  86.         if ($rootIds !== []) {
  87.             return $rootIds;
  88.         } else {
  89.             throw new Exception('Parent node do not exists.');
  90.         }
  91.     }
  92.  
  93.     protected function walkTree($node, &$output, $format, $depth = 0)
  94.     {
  95.         switch ($format) {
  96.             case Tree::FORMAT_TEXT:
  97.                 $output .= $this->formatNodeAsText($node['text'], $depth);
  98.                 break;
  99.             case Tree::FORMAT_HTML:
  100.                 $output .= $this->formatNodeAsHtml($node['text'], $depth);
  101.                 break;
  102.             default:
  103.                 $output .= $this->formatNodeAsText($node['text'], $depth);
  104.         }
  105.         $depth += 1;
  106.  
  107.         if (isset($this->adjacencyList[$node['id']])) {
  108.         	foreach ($this->adjacencyList[$node['id']] as $childId) {
  109.             	$this->walkTree($this->nodes[$childId], $output, $format, $depth);
  110.         	}
  111.         }
  112.     }
  113.  
  114.     protected function formatNodeAsText($nodeText, $depth)
  115.     {
  116.         return str_repeat('    ', $depth) . $nodeText . "\r\n";
  117.     }
  118.  
  119.     protected function formatNodeAsHtml($nodeText, $depth)
  120.     {
  121.         return '<p class="offset-' . $depth . '">' . $nodeText . '</p>';
  122.     }
  123. }
  124.  
  125. $template = array(
  126.     array("id" => 1, "parentId" => null, "text" => "Первая строка"), 
  127.     array("id" => 2, "parentId" => 3,    "text" => "Вторая строка"), 
  128.     array("id" => 3, "parentId" => 1,    "text" => "Третья строка"),
  129.     array("id" => 4, "parentId" => 1,    "text" => "Четвертая строка"),
  130.  
  131.     array("id" => 5, "parentId" => null, "text" => "Пятая строка"), 
  132.     array("id" => 6, "parentId" => 5,    "text" => "Шестая строка")
  133. );
  134.  
  135. $tree = new Tree($template);
  136. echo $tree->format(Tree::FORMAT_TEXT);
Success #stdin #stdout 0.02s 24448KB
comments (?)
stdin
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Standard input is empty
stdout
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Первая строка
    Третья строка
        Вторая строка
    Четвертая строка
Пятая строка
    Шестая строка
https://ideone.com/5i21ND
language:
PHP (php 7.3.5)
created:
9 years ago
visibility:
secret

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