LeetCode 924: Minimize Malware Spread
Function prefix qualifiers
I seem to remember this being covered in your reviews before, but:
const inline size_t find(const size_t x)

This benefits from neither of the const declarations nor the inline. Both the return value and the argument are passed-by-value scalars and do not benefit from const. inline, for all intents and purposes, has no effect, particularly where a compiler is told to optimize your code - and even if it did have an effect, it's a bad idea to tell the optimizer what it should and shouldn't inline. It will understand what's good for your code better than the programmer does 99% of the time.
If these concepts are confusing or difficult to apply to code on a practical basis, that is understandable - feel free to ask follow-up questions.