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, 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?