下面是我的阵列。我想制作所有可能的数组合，其总和等于某个数字（例如20）。超级父阵列是大陆，它的子阵列是它的国家和国家子阵列是它各自的城市。我想获得城市总和days_range等于某个数字（例如20）的所有国家组合。这只是一个大陆阵列。有可能该阵列也适用于其他大陆。
Array
(
[1] => Array
(
[10] => Array
(
[0] => Array
(
[id] => 18
[city_name] => Baku
[country_id] => 10
[country_name] => Azerbaijan
[days_range] => 5
[continent_id] => 1
)
[2] => Array
(
[id] => 43
[city_name] => Lahıc
[country_id] => 10
[country_name] => Azerbaijan
[days_range] => 5
[continent_id] => 1
)
)
[23] => Array
(
[0] => Array
(
[id] => 42
[city_name] => Vientiane
[country_id] => 23
[country_name] => Laos
[days_range] => 7
[continent_id] => 1
)
[1] => Array
(
[id] => 47
[city_name] => Vang Vieng
[country_id] => 23
[country_name] => Laos
[days_range] => 3
[continent_id] => 1
)
)
[20] => Array
(
[0] => Array
(
[id] => 37
[city_name] => Tamsui District
[country_id] => 20
[country_name] => Taiwan
[days_range] => 1
[continent_id] => 1
)
[1] => Array
(
[id] => 35
[city_name] => Taipei
[country_id] => 20
[country_name] => Taiwan
[days_range] => 3
[continent_id] => 1
)
)
[22] => Array
(
[2] => Array
(
[id] => 46
[city_name] => Maolin District
[country_id] => 20
[country_name] => Taiwan
[days_range] => 3
[continent_id] => 1
)
[3] => Array
(
[id] => 36
[city_name] => Tainan
[country_id] => 20
[country_name] => Taiwan
[days_range] => 3
[continent_id] => 1
)
)
)
)
Array(
[0]=Array(
[0]=>[10],
[1]=>[23],
)
[1]=Array(
[0]=>[10],
[1]=>[20],
[2]=>[22],
)
[2]=Array(
[0]=>[23],
[1]=>[20],
[2]=>[22],
)
)