I am working on a toy car which is following the "light" and I am totally new at raspberry pi and circuits.

In this [video][1], he is using 1 ldr. I need 3-4 ldr to turn the car to left or right. (I am planning to put ldrs to different side of the car and i will follow towards that which ldr returns me call like "here is the light").

Should i make different circuits(3-4 different circuits in the video) and connect to raspberry ? If so, should i use different ground and different voltage pins to each circuits? In short can i set like "pin3.3v and gnd for the circuit1 and **the other** 3.3v and gnd for the circuit2.. or can i use same ground for all different 3.3voltage pins?

what i want to do is like: [picture][2]
as you see in picture there are same but 2 different circuits(both connected to different 3.3voltages and grounds)

  [1]: https://www.youtube.com/watch?v=dPwW9zmX84E
  [2]: https://image.ibb.co/hDdhqo/Ekran_Al_nt_s.png