Deutsch-Jozsa Algorithm

The first quantum algorithm to prove exponential speedup over classical. Given a black-box function f(x), determine if it's constant (same output for all inputs) or balanced (different output for half the inputs) — in ONE query instead of 2^(n-1)+1.

Quantum

1
oracle query

Classical (worst case)

-
queries needed

Speedup

-
quantum advantage
The simplest proof that quantum computers can be exponentially faster than classical. | FreeQuantumStore