根据值排序关联数组

Question

在数组的每个元素中，第二个值指向元素本身的父元素。因此，例如在第一个数组中，“City”是根元素，“Area”是第一个子元素，因为第二个“Area”元素（1）指向“City”的键。

样本数据

$locations = array(
    3 => array("Building", 2),
    2 => array("Area", 1),
    0 => array("Floor", 3),
    1 => array("City"),
    4 => array("Room", 0),

    13 => array("Building1", 12),
    12 => array("Area1", 11),
    14 => array("Room1", 10),
    10 => array("Floor1", 13),
    11 => array("City1")
);

预期产出

Room > Floor > Building > Area > City

Room1 > Floor1 > Building1 > Area1 > City1

我的解决方案

$route = [];

foreach ($locations as $locationKey => $locationArray) {

    if (!isset($locationArray[1])) continue;

    $nextLocation = $locations[$locationArray[1]][0];
    $route[] = $nextLocation;
}

但是，它不会添加没有在数组中给出索引的数组，例如索引4 array("room", 0);

此外，如果一条路线完成，我无法弄清楚如何拆分路线

输出我得到：

Array
(
[0] => Area
[1] => City
[2] => Building
[3] => Floor
[4] => Area1
[5] => City1
[6] => Floor1
[7] => Building1
)

Answer 1

你可以这样做：

首先保存字典，了解如何获取每个节点和根：

$dic = [];
$roots = [];
foreach($locations as $k => $e) {
    if (count($e) == 2)
        $dic[$e[1]] = $k;
    else
        $roots[] = $k;
}

然后循环所有root并创建路径：

foreach($roots as $root) {
    $path = [];
    $node = $root;
    while (isset($dic[$node])) {
        $path[] = $locations[$node][0];
        $node = $dic[$node];
    }
    $path[] = $locations[$node][0];
    echo implode(",", array_reverse($path)) . PHP_EOL;
}

实例：3v4l