If you want to go for Engineering and especially you aim to take up Computer Science Engineering (CSE), then the below subjects are going to help you a lot!

1. Mathematics: Theoretical computer science is all about maths. You will be needing maths right from your first course which will be of discrete mathematics. Be it Machine Learning or Artificial Intelligence, you will be requiring maths at each and every step.

2. Coding (IP): You will be needing coding as it is going to be your bread and butter. Many software companies will require you to become a very good coder, and you will be compensated heftily for that.

Moreover, if you will enter deep in to CS like in graph theory, then at points you'll also be needing physics.

So, I would suggest you to go with PCM and along with it take Computer Science (CS) or Information Practices (IP). Hope I have answered your question. All the best!