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7/23/2019 Algorithms - String Processing - 01 - Trie
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Trie (Letter Tree)
Mostafa Saad
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TrieA simple but powerful data structure.
It adds/searches for string in O(L)
It is a tree with branches as letters
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7/23/2019 Algorithms - String Processing - 01 - Trie
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Initiall! root e"ist
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7/23/2019 Algorithms - String Processing - 01 - Trie
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Add abcd
a
d
c
b
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7/23/2019 Algorithms - String Processing - 01 - Trie
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Add "#
a
d
c
b
"
#
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7/23/2019 Algorithms - String Processing - 01 - Trie
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Add abf
a
d
c
b
"
#
f
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7/23/2019 Algorithms - String Processing - 01 - Trie
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Add "n
a
d
c
b
"
#
f
n
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7/23/2019 Algorithms - String Processing - 01 - Trie
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Add ab
a
d
c
b
"
#
f
n
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7/23/2019 Algorithms - String Processing - 01 - Trie
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Add bcd
a
d
c
b
"
#
f
n
d
c
b
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7/23/2019 Algorithms - String Processing - 01 - Trie
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SoSimple tree
$ommon pre%"es are created once
&as to 'now the nodes (red ones)
$ould answer uestions such as*oes word e"ist+ ,re-uenc+
*oes pre%" e"ist+ ,re-uenc+
An -uestion is answered b a trace from root toma"imum a leaf
So O(L) where L is word length
$ould also print all strings on O(S)! where S ofwords
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7/23/2019 Algorithms - String Processing - 01 - Trie
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Implementationode is similar to binar search tree! but we
ha0e man children$aring with memor+ &ither ha0e lin'ed list
for the set of nodes
Or more e1cient. 2se maps
Memor not issue3as an arra of nodes! its si#e the of
characters
ode could contain whate0er needed&.g. boolean to 'now full
words
&.g. integer for fre-uenc
