如何保留 keep 等于 1 的所有键，包括父键，删除 keep 等于 0 的所有键，$result 是 $origin 的结果

$origin = [
    'a' => [
        'keep' => 0
    ],
    'b' => [
        'keep' => 1
    ],
    'c' => [
        'd' => [
            'keep' => 1
        ],
    ],
    'e' => [
        'f' => [
            'keep' => 0
        ]
    ],
    'g' => [
        'h' => [
            'i' => [
                'keep' => 1
            ],
            'j' => [
                'keep' => 1
            ],
        ],
    ],
    'k' => [
        'l' => [
            'i' => [
                'keep' => 0
            ],
            'm' => [
                'keep' => 1
            ],
        ],
    ],
    'n' => [
        'o' => [
            'p' => [
                'keep' => 0
            ],
            'q' => [
                'keep' => 0
            ],
        ],
    ]
];

$result = [
    'b',
    'c' => [
        'd',
    ],
    'g' => [
        'h' => [
            'i',
            'j',
        ],
    ],
    'k' => [
        'l' => [
            'n',
        ],
    ],
];