String Searching
Authors: Benjamin Qi, Siyong Huang
Prerequisites
Knuth-Morris-Pratt and Z Algorithms (and a few more related topics).
Resources | |||
---|---|---|---|
CPC | String Matching, KMP, Tries | ||
CP2 |
Single String
KMP
Knuth-Morris-Pratt, or KMP, is a linear time string comparison algorithm that matches prefixes. Specifically, it computes the longest substring that is both a prefix and suffix of a string, and it does so for every prefix of a given string.
Resources | |||
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cp-algo | |||
PAPS | |||
GFG | |||
TC |
Status | Source | Problem Name | Difficulty | Tags | Solution | URL |
---|---|---|---|---|---|---|
Kattis | Easy | Show TagsStrings | Show Sketch | |||
POI | Easy | Show TagsStrings, prefix functions | External Sol | |||
Baltic OI | Normal | View Solution | ||||
POJ | Hard | Show TagsStrings | Show Sketch | |||
CEOI | Hard | View Solution |
Z Algorithm
The Z-Algorithm is another linear time string comparison algorithm like KMP, but instead finds the longest common prefix of a string and all of its suffixes.
Resources | |||
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cp-algo | |||
CPH | |||
CF |
Palindromes
Manacher
Manacher's Algorithm is functionally similarly to the Z-Algorithm and can compute information about palindromes. It can determine the longest palindrome centered at each character.
Resources | |||
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HR | |||
CF | shorter code | ||
cp-algo |
Don't Forget!
Palindromic Tree
A Palindromic Tree is a tree-like data structure that behaves similarly to KMP. Unlike KMP, in which the only empty state is , the Palindromic Tree has two empty states: length , and length . This is because appending a character to a palindrome increases the length by , meaning a single character palindrome must have been created from a palindrome of length
Resources | |||
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CF | |||
adilet.org |
Multiple Strings
Tries
A trie is a tree-like data structure that stores strings. Each node is a string, and each edge is a character. The root is the empty string, and every node is represented by the characters along the path from the root to that node. This means that every prefix of a string is an ancestor of that string's node.
Resources | |||
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CPH | |||
CF | |||
PAPS |
Aho-Corasick
Aho-Corasick is the combination of trie and KMP. It is essentially a trie with KMP's "fail" array.
Warning!
Build the entire trie first, and then run a BFS to construct the fail array.
Resources | |||
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cp-algo | |||
CF | |||
GFG |
Status | Source | Problem Name | Difficulty | Tags | Solution | URL |
---|---|---|---|---|---|---|
Gold | Normal | Show TagsStrings | External Sol | |||
CF | Normal | Show TagsStrings | Check CF |
This section is not complete.
1731 Word Combinations -> trie 1753 String Matching -> string search 1732 Finding Borders -> string search 1733 Finding Periods -> string search 1110 Minimal Rotation -> string search 1111 Longest Palindrome -> string search 1112 Required Substring -> string search
Module Progress:
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