  A "bucket brigade" architecture for a quantum random memory of $N=2^n$ memory
cells needs $n(n+5)/2$ times of quantum manipulation on control circuit nodes
per memory call. Here we propose a scheme, in which only average $n/2$ times
manipulation is required to accomplish a memory call. This scheme may
significantly decrease the time spent on a memory call and the average overall
error rate per memory call. A physical implementation scheme for storing an
arbitrary state in a selected memory cell followed by reading it out is
discussed.
