## June 1, 2018

# Deutch's Algorithm (or Two Birds One Quantum Gate)

Why is this important? Let’s say we have to find a binary function $f$, but we are only given the gate $U_f$ and our goal is to guess what $f$ could be based on the output of a circuit. (Don’t worry about the specifics of the gate, it can be a black box for now.) Classically, it should take two evaluations of the function just to determine the following result: $f(0) \oplus f(1)$.
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