Three Stack Implemention Using an Array?

Hello everyone, I know how to efficiently use an array to implement two stack,

Algorithm works as Put Top1 as -1 it means first stack will grow from Left to write and put Top2 as Max+1 , This(second) stack will grow from Right to Left,

Now can anybody please explain how to efficiently use an array to implement three stack.

Thanks and Happy Coding , Algorithm with Sudo Code will be very appreciable.