**Input:** Three qubits (stored in an array of length 3) in an arbitrary three-qubit state 
$\alpha |000\rangle + \beta |001\rangle + \gamma |010\rangle + \delta |011\rangle + \epsilon |100\rangle + \zeta|101\rangle + {\color{blue}\eta}|110\rangle + {\color{blue}\theta}|111\rangle$.

**Goal:** Flip the state of the third qubit if the state of the first two is $|11\rangle$, i.e., change the three-qubit state to $\alpha |000\rangle + \beta |001\rangle + \gamma |010\rangle + \delta |011\rangle + \epsilon |100\rangle + \zeta|101\rangle + {\color{red}\theta}|110\rangle + {\color{red}\eta}|111\rangle$.