Topics / Strings
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Strings
String manipulation problems — palindromes, anagrams, pattern matching, and substring tricks.
Why learn Strings?
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Second-most-common interview topic after arrays.
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Teaches you to think in characters, indices, and frequencies at once.
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Patterns transfer directly to bioinformatics, parsers, and search.
What you can build with Strings
Palindrome and anagram problems Substring search and pattern matching Text editors and string-heavy backends
Strings tutorials
7 articlesHand-written tutorials, ordered as a recommended learning path.
- 01 Strings A practical guide to JavaScript strings — template literals, indexing, the essential methods, immutability, and the modern ways to slice, search, and transform text.
- 02 Strings A thorough introduction to Python strings — creation, escape sequences, indexing, slicing, the essential methods, f-strings, and why strings are immutable.
- 03 Strings — Intro An introduction to strings for data structures and algorithms — immutability, indexing, slicing, common operations, ASCII versus Unicode, and the two-pointer and frequency-counter patterns you will use everywhere.
- 04 Pattern Matching A practical tour of substring search — the naive O(n·m) scan, the KMP algorithm with its LPS array, and the Rabin-Karp rolling hash. Worked examples, code, and intuition for when to use each.
- 05 Strings — Practice Eight classic string problems with worked Python solutions — Valid Anagram, Group Anagrams, Longest Substring Without Repeating Characters, Longest Palindromic Substring, and more.
- 06 LC 72 — Edit Distance LeetCode 72 fully unpacked — the three-operation recurrence, the 2D table, and the rolling-array space optimization that makes interviewers nod.
- 07 Longest Palindrome Walk through LeetCode Longest Palindromic Substring using the expand-around-center technique. Compare brute force, DP, and the optimal approach with examples.