大規模な PHP 配列の交差と結合を処理するための実用的なソリューション

$arr1 = range(1, 1000000);
$arr2 = range(500001, 1500000);

$hash = array_flip($arr1);

$intersection = array_keys(array_intersect_key($hash, $arr2));

use Hashes\Hash;

$map = new Hash();
foreach ($arr1 as $val) {
    $map->add($val);
}

$intersection = $map->intersect($arr2);
$union = $map->union($arr2);

function bitInterset($arr1, $arr2) {
    $max = max(max($arr1), max($arr2));
    $bitSize = 32;  // 如果 max > (2^32 - 1)，可以调整 bitSize

    $bitmap1 = array_fill(0, $bitSize, 0);
    $bitmap2 = array_fill(0, $bitSize, 0);

    foreach ($arr1 as $num) {
        $bitmap1[$num >> 5] |= (1 << ($num & 31));
    }
    foreach ($arr2 as $num) {
        $bitmap2[$num >> 5] |= (1 << ($num & 31));
    }

    $intersection = [];
    for ($i = 0; $i < $bitSize; $i++) {
        $mask = $bitmap1[$i] & $bitmap2[$i];
        for ($j = 0; $j < 32; $j++) {
            if (($mask >> $j) & 1) {
                $intersection[] = ($i << 5) | $j;
            }
        }
    }

    return $intersection;
}