On the average depth of asymmetric LC-tries
Andersson and Nilsson have already shown that the average depth D n of random LC-tries is only Θ ( log ∗ n ) when the keys are produced by a symmetric memoryless process, and that D n = O ( log log n ) when the process is asymmetric. In this paper we refine the second estimate by showing that asympt...
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Published in | Information processing letters Vol. 96; no. 3; pp. 106 - 113 |
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Main Author | |
Format | Journal Article |
Language | English |
Published |
Amsterdam
Elsevier B.V
15.11.2005
Elsevier Science Elsevier Sequoia S.A |
Subjects | |
Online Access | Get full text |
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Summary: | Andersson and Nilsson have already shown that the average depth
D
n
of random LC-tries is only
Θ
(
log
∗
n
)
when the keys are produced by a symmetric memoryless process, and that
D
n
=
O
(
log
log
n
)
when the process is asymmetric. In this paper we refine the second estimate by showing that asymptotically (with
n
→
∞
):
D
n
∼
1
η
log
log
n
, where
n is the number of keys inserted in a trie,
η
=
−
log
(
1
−
h
/
h
−
∞
)
,
h
=
−
p
log
p
−
q
log
q
is the entropy of a binary memoryless source with probabilities
p,
q
=
1
−
p
(
p
≠
q
), and
h
−
∞
=
−
log
min
(
p
,
q
)
. |
---|---|
ISSN: | 0020-0190 1872-6119 |
DOI: | 10.1016/j.ipl.2005.06.008 |