For me , this is not best practise , because you will calculate the min and max while the input array is already sorted , view my solution.

Better case is:
$this->assertSame(9199999999999999999, nextBigger(1999999999999999999));

This seems quciker then what i wrote lol

Be very carefull with eval. Basically you should not do it. And if you do - sanitize input.

i agree it will re execute the count in each iteration, but maybe he leave it like that to save 1 line of code at the cost of little eficiency.

A pleasure sir, it's always worth trying to formulate any constraints until you find a set that can be resolved.

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

Your testcase is wrong. The next bigger value of 1111111111111111119 is 1111111111111111191.

But your assumption is right: Searching for the solution iteratively is wasting lots of CPU, so this isn't qualifying as "clever" in the sense of "using an approach that is not brute-forcing it, but identifying the problem as what it truly is, and applying a very good solution to it".

But it might qualify for "clever" as in "applying a solution that isn't obvious".

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.