Why this code show error

Question

https://sololearn.com/compiler-playground/cs7ZJqoTxdp2/?ref=app

Answer 1

sololearn is a learning platform, and the playground is just a sandbox. i don't know if or how we can install additional libraries, but I doubt that we can arbitrarily install everything.

Answer 2

Yeah tnx you🙏🏻

Answer 3

There is no OR_Tool?

Answer 4

How can i add this extenstion?