Algorithm - PHP converts an array of paths into a directory tree

<code class="php"><?php
$paths = ['aa','aa/bb/bb','ww/yyy/bb','aa/kk','xx/oo/pp'];

$arr = [];//先定义一个空数组用来存储所有路径。

//循环找出所有路径
foreach($paths as $v){
    $path = explode('/',$v);
    $temp = '';
    foreach($path as $k2=>$v2){
        $temp .= empty($temp)?$v2:'/'.$v2;
        $arr[$temp] = $temp;
    }
}

sort($arr); //排序

//循环输出
foreach($arr as $v){
    $path = explode('/',$v);
    $n = count($path);
    echo line($n).$path[$n-1]."\n";
}


function line($n){
    $line = '';
    for($i=1;$i<$n;$i++){
        $line .= '-';
    }
    return $line;
}</code>

<code>元素  id  pid
aa    1   0
bb    2   1
ww    3   0
yyy   4   3
kk    5   1
xx    6   0
oo    7   6
pp    8   7 </code>

<code class="php">// 重排数组
$paths = ['aa','aa/bb','ww/yyy','aa/kk','xx/oo/pp'];
sort($paths);
// 得到结果数组：k为值，v为前面-
$res = [];
foreach ($paths as $v) {
    // 拆分路径
    $path = explode('/', $v);
    foreach ($path as $k1 => $v1) {
        // 此项前面几个-
        $res[$v1] = '';
        for ($i=0; $i < $k1; $i++) {
            $res[$v1] .= '-';
        }
    }
}
// 输出
foreach ($res as $k => $v) {
    echo "$v$k<br>";
}</code>

<code>  // 把这类数据转换成无限级格式...
  $paths = ['aa','aa/bb/bb','ww/yyy/bb','aa/kk','xx/oo/pp'];
  $data = [];
  $id = 0;
  foreach($paths as $path){
    $tmps = explode('/', $path);
    $parent = '';
    foreach($tmps as $v){
      $parentID = $parent == '' ? 0 : $data[$parent]['id'];
      $parent .= $parent == '' ? $v : '/' . $v;
      if( ! isset($data[$parent]) ){
        $id++;
        $tmp = array(
          'id' => $id,
          'parent_id' => $parentID,
          'key' => $v,
          'path' => $parent,
        );
        $data[$parent] = $tmp;
      }
    }
  }
  
  print_r($data);

  // 再以无限级方式处理数据 $data 
</code>