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

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