The Quantum Engineer

F. Common Quantum Algorithms

The canon, one line each (details in Part VII chapters cited): Deutsch (Ch. 19) — one query decides f(0)⊕f(1); first quantum win. Deutsch–Jozsa (20) — constant vs. balanced, one query, deterministic. Bernstein–Vazirani (21) — recovers hidden string a exactly, one query. Simon (22) — hidden XOR mask via QFT-period structure; Shor's direct ancestor. QFT (23) — quantum Fourier transform, O(n²) vs classical FFT's O(n2ⁿ); periodicity extractor. Phase estimation (24) — eigenphases to k bits; simulation and Shor's engine. Grover (25) — √ search speedup, provably optimal (BBBV). Shor (26) — factoring/discrete-log in quantum polynomial time; the applications-world earthquake (Ch. 51). VQE (49) — variational ground states; NISQ's hello-world. QAOA (49) — variational combinatorial optimization. HHL (49.5-adjacent) — linear systems under heavy caveats. Quantum walks, amplitude amplification/estimation, QSVT/qubitization (28.7–28.8, 79) — the modern primitive layer. Selection rule from Ch. 28: structural (exponential) vs. generic (quadratic) vs. sampling vs. simulation — classify before quoting.