Quantum Computing.
Let’s say that the smallest j such that ƒ(j) = r is j_1 and since the j’s increase in steps of o integers we can write as well | ƒ(j) = r⟩ = √o/L (|j_1⟩ + … + |j_1 + ko⟩ + … + |j_1 + L — o) ⟩ ) Quantum circuit diagram of a quantum phase estimation algorithm. Now we can apply the inverse QFT and get