11.7 Summary

In this chapter, we looked at classical linear and binary search. In the first case, the items in the collection were not ordered initially, and so we were forced to look at each item in turn to locate the one we sought. When we could assume the items were sorted, the binary search method was much more efficient as we could iteratively divide the problem size in half until we got our result. We then turned to one of the most accessible quantum algorithms, Grover search. Using Grover, the search time became proportional to the square root of the number of items.

An important caveat with the Grover algorithm is that quantum computers today cannot process large enough collections of data so that it is practically more efficient than classical methods. Nevertheless, it is an excellent example of where and how we might get a quantum advantage.