 Unknown input size:
 The number of inputs data
is unknown when the
algorithm is running
 We can try to adjust to
data structures used to retain the
input data
(by using linked list)
 Sometimes, the input size
may be too large
to be stored completely and
the algorithm must
run using
a partial input
(and readjust the result
when new inputs are red in)

 Incomplete information:
 This is a result from the
unknown input size:
the algorithm must
run using
a partial input
Because the algorithm
does not know
the whole input,
an online algorithm
is forced
to
make algorithmic decisions
that may later turn out
not to be optimal.
Often, online algorithms will
compute solutions that must be
nonoptimal and
the study of online algorithms
focuses
on the quality of solution
opbatined using
incomplete information
(e.g., max. 1% from the optimum value)

