Thank you for the comments on your solution

It's a shame that I didn't think of this solution myself.
Although initially I wrote down these dependencies in the form of a system of equations. But I did not guess to express the time of the walk through the time by taxi.

Thank you very much.

Fixed tests. And now your solution doesn't work. I'm sorry. :)

Thanks. I will add a test

I know about this. it is a very hard problem. Only one small assert and 6 months. :)

Guys, is this the best solution or clever?
Here's a simple additional test for you.

$this->assertSame(1911111111111111111, nextBigger(1111111111111111119));

And then enjoy how your solution will work.

Hi
Nice solution.

Can you explain me why you are write this code: round($value * 4 * 1.e10) / 1.e10 ?
I replaced this with: $value * 4 and submit work correctly.

I think it is not a best practice: $i < count($arr)

You can remove break without problem. :)