I am new to QC and right now trying to understand Grover’s algorithm. In Qiskit documents, in the section about solving Sudoku using Grover’s, the first step is explained to be creating three register: $|x\rangle$ $|c\rangle$ and $|out\rangle$
The next step is to initialize $|x\rangle$ by $H|0\rangle$. I get up to here.
Then we apply controlled Not gates to flip the $|c\rangle$ (clause) registers. Here I am stuck because I thought doing a CNOT on $|0+\rangle$ leads to entangled states.
The Qiskit document is here:
Do the states really get entangled and if so how can the rest of the circuit work whilst considering the individual qubits?