  We show how to select an item with the majority color from $n$ two-colored
items, given access to the items only through an oracle that returns the
discrepancy of subsets of $k$ items. We use $n/\lfloor\tfrac{k}{2}\rfloor+O(k)$
queries, improving a previous method by De Marco and Kranakis that used
$n-k+k^2/2$ queries. We also prove a lower bound of $n/(k-1)-O(n^{1/3})$ on the
number of queries needed, improving a lower bound of $\lfloor n/k\rfloor$ by De
Marco and Kranakis.
