It's not a homework problem, although I can see how it
might look like one. The problem arises in something
we're looking at involving quantum entanglement - each of
the a[i][0] +
a[i][1] terms
(i=0, 1, 2, ..., N-1)
represents a two-level quantum state.
N such terms multiplied together thus represents
a product state of N two-level states. We're
then seeing if a general state can be written in this
form - if it cannot, then the degree to which it can't is
a measure of the degree of entanglement.