A q-ary code C of length n is a set of n-dimensional vectors (codewords) with entries in \(\{0, \ldots , q-1\}\) . We say C has constant weight w if each codeword has exactly w nonzero entries. We say C has minimum distance d if any two distinct codewords in C differ in at least d entries. We let \(A_q(n, d, w)\) be the largest possible cardinality of any q-ary code of length n with constant weight w and minimum distance d. Very recently, Liu and Shangguan gave an asymptotically sharp estimate for \(A_q(n, d, w)\) where q, d, w are fixed, d is odd and \(n \rightarrow \infty \) . In this note we answer a question of Liu and Shangguan by obtaining such an estimate in the case where d is even.
