Good Problem(s) on 'AND' operation?!?!

I am searching for good problems which involves the โ€˜andโ€™ operation specifically,sometimes with bit manipulation tricks and sometimes with bit-masking techniques + segment trees!

I was only able to find 2-3 problems like these, can you suggest some more ? :slight_smile:
I would love all the suggestions!!

There is a running contest on hackerearth which has a question on and operation. You may want to check it out.

Link to the contest and question

I already know that, something from codechef is what Iโ€™m looking for!