  The number of states and stack symbols needed to determinize nondeterministic
input-driven pushdown automata (NIDPDA) working over a fixed alphabet is
determined precisely. It is proved that in the worst case exactly 2^{n^2}
states are needed to determinize an n-state NIDPDA, and the proof uses witness
automata with a stack alphabet \Gamma = {0,1} working on strings over a
4-symbol input alphabet (Only an asymptotic lower bound was known before in the
case of a fixed alphabet). Also, the impact of NIDPDA determinization on the
size of stack alphabet is determined precisely for the first time: it is proved
that s(2^{n^2}-1) stack symbols are necessary in the worst case to determinize
an n-state NIDPDA working over an input alphabet of size s+5 with s left
brackets (The previous lower bound was only asymptotic in the number of states
and did not depend on the number of left brackets).
