Straight to number one in music culture means a song is released and the next week it is top of the song charts.

"Cry me a river" is a sarcastic way to say "I don't care." You could cry until your tears became a river, I still wouldn't care. For example, my child insists on banging his toy sword against a tree and I warn him not to. The sword breaks. "Cry me a river, kid! I told you that would happen." Another one my mother would use when I was a child was "oh for crying in a bucket." Again, it is a way of signifying worthless tears and futility. I never understood the origin of that phrase, possibly the futility of collecting tears in a bucket. "Straight to number one" is not one I hear very often. I think it means going straight to the person in charge, but where I live we would say "straight to the top" for that. Good luck with your studies.

This simply means what ever you do its none of my business.

I saw your question and it automatically made me think of this song: Cry Me a River by Justin Timberlake: https://www.youtube.com/watch?v=DksSPZTZES0 I'm a sucker for a good pop song, especially when it ties into an explanation :-) You told me you loved me Why did you leave me, all alone Now you tell me you need me When you call me, on the phone Girl I refuse, you must have me confused With some other guy Your bridges were burned, and now it's your turn To cry, cry me a river Cry me a river-er Cry me a river Cry me a river-er, yea yea