Groover Algorithm

Grover’s algorithm, which is a quantum algorithm for so-called unstructured search problems that offers a quadratic improvement over classical algorithms. What this means is that Grover’s algorithm requires a number of operations on the order of the square-root of the number of operations required to solve unstructured search classically — which is equivalent to saying that classical algorithms for unstructured search must have a cost at least on the order of the square of the cost of Grover’s algorithm. Grover’s algorithm, together with its extensions and underlying methodology, turn out to be broadly applicable, leading to a quadratic advantage for many interesting computational tasks that may not initially look like unstructured search problems on the surface. source-IBM please read more here