https://s8a.jp/php-fast-array-diff - 1

array_diff.php

<?php

$array1 = range(50000, 200000);
$array2 = range(0, 100000);

shuffle($array1);
shuffle($array2);

$timeStart = microtime(true);

array_diff($array1, $array2);

$timeFinish = microtime(true);

echo '処理時間: ' . ($timeFinish - $timeStart) . '秒' . PHP_EOL;

fast_array_diff.php

<?php

$array1 = range(50000, 200000);
$array2 = range(0, 100000);

shuffle($array1);
shuffle($array2);

$timeStart = microtime(true);

fast_array_diff($array1, $array2);

$timeFinish = microtime(true);

echo '処理時間: ' . ($timeFinish - $timeStart) . '秒' . PHP_EOL;

function fast_array_diff()
{
  return array_flip(call_user_func_array('array_diff_key', array_map('array_flip', func_get_args())));
}