<s>
In	O
computer	B-General_Concept
science	I-General_Concept
,	O
a	O
pile	O
is	O
an	O
abstract	O
data	O
type	O
for	O
storing	O
data	O
in	O
a	O
loosely	O
ordered	O
way	O
.	O
</s>
<s>
There	O
are	O
two	O
different	O
usages	O
of	O
the	O
term	O
;	O
one	O
refers	O
to	O
an	O
ordered	O
double-ended	B-Application
queue	I-Application
,	O
the	O
other	O
to	O
an	O
improved	O
heap	B-Application
.	O
</s>
<s>
The	O
first	O
version	O
combines	O
the	O
properties	O
of	O
the	O
double-ended	B-Application
queue	I-Application
(	O
deque	B-Application
)	O
and	O
a	O
priority	B-Application
queue	I-Application
and	O
may	O
be	O
described	O
as	O
an	O
ordered	O
deque	B-Application
.	O
</s>
<s>
Piles	O
of	O
this	O
kind	O
are	O
used	O
in	O
the	O
"	O
UnShuffle	O
sort	O
"	O
sorting	B-Algorithm
algorithm	I-Algorithm
.	O
</s>
<s>
The	O
second	O
version	O
is	O
a	O
subject	O
of	O
patents	O
and	O
improves	O
the	O
heap	B-Application
data	I-Application
structure	I-Application
.	O
</s>
