<s>
In	O
computer	B-General_Concept
science	I-General_Concept
and	O
operations	O
research	O
,	O
exact	B-Algorithm
algorithms	I-Algorithm
are	O
algorithms	O
that	O
always	O
solve	O
an	O
optimization	O
problem	O
to	O
optimality	O
.	O
</s>
<s>
Unless	O
P	O
=	O
NP	O
,	O
an	O
exact	B-Algorithm
algorithm	I-Algorithm
for	O
an	O
NP-hard	O
optimization	O
problem	O
cannot	O
run	O
in	O
worst-case	O
polynomial	O
time	O
.	O
</s>
<s>
There	O
has	O
been	O
extensive	O
research	O
on	O
finding	O
exact	B-Algorithm
algorithms	I-Algorithm
whose	O
running	O
time	O
is	O
exponential	O
with	O
a	O
low	O
base	O
.	O
</s>
