Find ids in tree array by parent id includes parent id(recursively)

findIdsByParentId.php

<?php
/**
* @author iron-viper
*/
$array = [
    [
        "id" => 1,
        "name" => "test-1",
        "parent" => 0,
        "children" => [
            [
                "id" => 11,
                "name" => "test-11",
                "parent" => 1,
                "children" => [
                    [
                        "id" => 111,
                        "name" => "test-111",
                        "parent" => 11,

                    ],
                    [
                        "id" => 112,
                        "name" => "test-112",
                        "parent" => 11,

                    ]
                ]
            ]
        ]
    ],
    [
        "id" => 2,
        "name" => "test-2",
        "parent" => 0
    ],
    [
        "id" => 3,
        "name" => "test-3",
        "parent" => 0,
        "children" => [
            [
                "id" => 31,
                "name" => "test-31",
                "parent" => 3,
                "children" => [
                    [
                        "id" => 311,
                        "name" => "test-111",
                        "parent" => 31,
                        "children" => [
                            [
                                "id" => 411,
                                "name" => "test-111",
                                "parent" => 311,

                            ]
                        ]

                    ]
                ]
            ],
            [
                "id" => 321,
                "name" => "test-111",
                "parent" => 3,
            ]
        ]

    ]
];

function find($id, $array, &$res)
{
    foreach ($array as $row) {
        if ($row["id"] == $id || $row["parent"] == $id) {
            $res[] = $row["id"];

            if ($row["children"]) {
                find($row["id"], $row["children"],$res);
            }
        } else {
            if ($row["children"]) {
                find($id, $row["children"],$res);
            }
        }
    }
}

// example
find(31, $array, $res);

var_dump($res);

/* result
array(3) {
  [0]=>
  int(31)
  [1]=>
  int(311)
  [2]=>
  int(411)
}
*/