数组A，有一千万个数，数组B同样也有千万多个数，然后从A和B当中随意找一个数字A1和B1,A1-B的绝对值是C，保证C最小。求A1和B1

        $a = [-11, -5, -9, -3, -2, -1];        $b = [-20, -13, -4, 6, 77, 200];        $key = $a[rand(0, count($a) - 1)];        sort($b);        echo "\n=====================\n";        print_r($b);        echo $key . "\n=====================\n";        if (count($b) > 1) {            foreach ($b as $k => $v) {                if ($key == $v) {                    $minAbs = 0;                    echo "loca:{$k,abs{$minAbs} \n";                    exit;                }                if ($key > $v) {// echo $v."," ;                } else {                    $last = $b[$k - 1];                    $next = $b[$k + 1];                    $curr = $b[$k];                    echo "\n" . $last, "\t <", $curr, ">\t", $next;                    $min = min(abs($key - $next), abs($key - $curr), abs($key - $last));                    echo "\n min abs:" . $min;                    exit;                }            }        } else {            echo abs($key - $a[0]);        }