求高效演算法找

$a = array(    'A' => array(1,2,3,4,5,6),    'B' => array(1,7,8,9),    'C' => array(1,6,7,8,9),)        $b = array(    '2','4')    求高效演算法找出 $b數組  屬於數組 $a  A、B、C的那一項的子集，注 $a,$b 數量不確定  

回複討論(解決方案)

$a = array(    'A' => array(1,2,3,4,5,6),    'B' => array(1,7,8,9),    'C' => array(1,6,7,8,9),);     $b = array(    '2','4');$r = array_filter($a, function($t) use ($b) {  return array_intersect($b, $t) == $b;});print_r($r);

Array(    [A] => Array        (            [0] => 1            [1] => 2            [2] => 3            [3] => 4            [4] => 5            [5] => 6        ))

foreach ($a as $key => $aa) {    if (count($aa) == count(array_flip(array_merge($aa, $b)))) {        echo $key;        break;    }}

不知道這個算不算高效

$a = array(    'A' => array(1,2,3,4,5,6),    'B' => array(1,7,8,9),    'C' => array(1,6,7,8,9),);     $b = array(    '2','4');$r = array_filter($a, function($t) use ($b) {  return array_intersect($b, $t) == $b;});print_r($r);

Array(    [A] => Array        (            [0] => 1            [1] => 2            [2] => 3            [3] => 4            [4] => 5            [5] => 6        ))

牛比。。

