Parking Dilemma - Company-specific OAs / Twitter OA

You are in charge of a linear parking lot. There are n cars parked permanently in this parking lot. The ith car occupies the pos[i]th parking slot. You feel bad for the car owners of these cars, so you decided to build a roof to cover k cars from the rain. Why build just a singular roof and why only cover k cars instead of every car? You didn't get paid enough for this.

This is a companion discussion topic for the original entry at