Grover's algorithm

One of the most famous quantum algorithms is Grover's search algorithm that achieves a quadratic speed-up over any classical algorithm. A simple way of understanding Grover's algorithm is in terms of amplitude amplification, which is a technique for manipulating the amplitudes of quantum states. It shows that the benefits of Grover's algorithm carry over to arbitrary search processes and settings, and that a quadratic speed-up can be achieved for many problems.