Approved

C++ test lacks the std namespace usage. Can't run them without adding it.

Fixed.

OK, changed for better understanding.

"leaf of the current root".

In this case, leaf == child, meaning a root has children, they are leafs.

Thanks for the pointer. If the tree cannot be inverted, one should return the original one.
Added this information and tests for such cases.

Solved issues with random tests.

I've finally got the point about mutability and safety of a random function. Thanks, fixed.

Currently, Kata has unresolved issue with tests.

Thanks for your feedback, I've updated my solution.

• Removed redundant test random years more than two;
• Added repeating the test 100 times;
• Made 40 years old dogs and cats. As I've googled, the oldest cat was 39 (wrote 38, re-googled and found an older one :D), the oldest dog was 29.
• Added one minor refactoring change.