Share the most convenient and fastest way to calculate the remaining time of the day in PHP

echo strtotime('23:59:59')-time();

$now = time();
echo 86400-date('H', $now)*3600- date('i', $now)*60-date('s');

echo 86400-(time()+8*3600)%86400;

xubanditdeMacBook-Pro:~ xubandit$ time php -f a.php

real    0m31.146s
user    0m30.966s
sys    0m0.075s
xubanditdeMacBook-Pro:~ xubandit$ time php -f b.php

real    0m48.574s
user    0m48.329s
sys    0m0.098s
xubanditdeMacBook-Pro:~ xubandit$ time php -f c.php

real    0m11.156s
user    0m10.786s
sys    0m0.098s
xubanditdeMacBook-Pro:~ xubandit$ cat a.php
<?php
for($i=0;$i<10000000;$i++){
    strtotime('23:59:59')-time();
}
xubanditdeMacBook-Pro:~ xubandit$ cat b.php
<?php
for($i=0;$i<10000000;$i++){
    $now = time();
    86400-date('H', $now)*3600- date('i', $now)*60-date('s');
}
xubanditdeMacBook-Pro:~ xubandit$ cat c.php
<?php
for($i=0;$i<10000000;$i++){
    86400-(time()+8*3600)%86400;
}