  Given two unsorted lists each of length N that have a single common entry, a
quantum computer can find that matching element with a work factor of
$O(N^{3/4}\log N)$ (measured in quantum memory accesses and accesses to each
list). The amount of quantum memory required is $O(N^{1/2})$. The quantum
algorithm that accomplishes this consists of an inner Grover search combined
with a partial sort all sitting inside of an outer Grover search.
