Strings

Deep

Strings matter because many pattern problems are really about structure in sequences.

Use This Area When

• the problem is about repeated pattern checks, substring structure, or many string queries
• exact matching matters more than raw simulation
• the right mental model is prefixes, automata, palindromes, or suffix structures

Start With One Route

If your bottleneck is...	Open first	Then
one-pattern exact matching	KMP	Z-Function, then Hashing
many patterns or dictionary matching	Trie	Aho-Corasick
palindrome structure	Palindromes / Manacher	Eertree / Palindromic Tree
full substring index structures	Suffix Array And LCP	Suffix Automaton, Suffix Tree

Core Progression

1. Core first
2. KMP
3. Z-Function

4. Hashing

5. Then add

6. Palindromes / Manacher
7. Trie / Aho-Corasick

8. Suffix Array And LCP

9. Deep later

10. Eertree / Palindromic Tree
11. Regular Expressions / Finite Automata
12. Suffix Automaton
13. Suffix Tree

Good First Repo Anchors

• Finding Borders
• Finding Periods
• Longest Palindrome
• Finding Patterns
• Pattern Positions

Browse All Subtopics

• Hashing
• KMP
• Z-Function
• Palindromes / Manacher
• Eertree / Palindromic Tree
• Trie
• Aho-Corasick
• Regular Expressions / Finite Automata
• Suffix Tree
• Suffix Array And LCP
• Suffix Automaton

Go Deeper

• Reference: CP-Algorithms
• Reference: OI Wiki
• Practice: ICPC Problem Archive
• Practice: CSES Problem Set
• Reference: KACTL