String Study Guide
==================

:::warning
[< Return to Home Page](https://hackmd.io/@siansiansu/HknJJm0W0)
:::

Basic String Operations
-----------------------

- 🟩 [14\. Longest Common Prefix](https://leetcode.com/problems/longest-common-prefix/) \[[Solution](https://hackmd.io/@siansiansu/B10ckhuzA)\]
- 🟩 [58\. Length of Last Word](https://leetcode.com/problems/length-of-last-word/) \[[Solution](https://hackmd.io/@siansiansu/HyT0tdKEC)\]
- 🟨 [151\. Reverse Words in a String](https://leetcode.com/problems/reverse-words-in-a-string/) \[[Solution](https://hackmd.io/@siansiansu/Hy7dVcYEA)\]
- 🟩 [2259\. Remove Digit From Number to Maximize Result](https://leetcode.com/problems/remove-digit-from-number-to-maximize-result/) \[[Solution](https://hackmd.io/@siansiansu/Skcyopun0)\]
- 🟩 [2678\. Number of Senior Citizens](https://leetcode.com/problems/number-of-senior-citizens/) \[[Solution](https://hackmd.io/@siansiansu/H1Ty0etKA)\]
- 🟨 [3216\. Lexicographically Smallest String After a Swap](https://leetcode.com/problems/lexicographically-smallest-string-after-a-swap/) \[[Solution](https://hackmd.io/@siansiansu/H1q91kZ_A)\]
- [1684. Count the Number of Consistent Strings](https://leetcode.com/problems/count-the-number-of-consistent-strings/description/) [[Solution](https://hackmd.io/@siansiansu/ryV6GRJaA)]

String Conversion and Manipulation
----------------------------------

- 🟨 [6\. Zigzag Conversion](https://leetcode.com/problems/zigzag-conversion/) \[[Solution](https://hackmd.io/@siansiansu/H1WRsqtER)\]
- 🟨 [8\. String to Integer (atoi)](https://leetcode.com/problems/string-to-integer-atoi/) \[[Solution](https://hackmd.io/@siansiansu/rk-JRVe7A)\]
- 🟨 [271\. Encode and Decode Strings](https://leetcode.com/problems/encode-and-decode-strings/) \[Solution\]
- 🟥 [65\. Valid Number](https://leetcode.com/problems/valid-number/) \[Solution\]

String and Numeric Operations
-----------------------------

- 🟨 [179\. Largest Number](https://leetcode.com/problems/largest-number/) \[[Solution](https://hackmd.io/@siansiansu/B1nntQxXC)\]
- 🟩 [1869\. Longer Contiguous Segments of Ones than Zeros](https://leetcode.com/problems/longer-contiguous-segments-of-ones-than-zeros/description/) \[[Solution](https://hackmd.io/@siansiansu/rJbcjxOh0)\]

Palindrome Problems
-------------------

- 🟥 [336\. Palindrome Pairs](https://leetcode.com/problems/palindrome-pairs/) \[Solution\]
- 🟨 [1328\. Break a Palindrome](https://leetcode.com/problems/break-a-palindrome/) \[[Solution](https://hackmd.io/@siansiansu/Hy7AawuL0)\]

Advanced String Algorithms
--------------------------

### String Matching

Knuth-Morris-Pratt (KMP) Algorithm
----------------------------------

- 🟨 [28\. Find the Index of the First Occurrence in a String](https://leetcode.com/problems/find-the-index-of-the-first-occurrence-in-a-string/) \[[Solution](https://hackmd.io/@siansiansu/rJKbnqcdC)\]

Rabin-Karp Algorithm
--------------------

- 🟨 [187\. Repeated DNA Sequences](https://leetcode.com/problems/repeated-dna-sequences/)

Manacher's Algorithm
--------------------

- 🟨 [5\. Longest Palindromic Substring](https://leetcode.com/problems/longest-palindromic-substring/) \[[Solution](https://hackmd.io/@siansiansu/HyGXCfzmC)\]

### Trie (Prefix Tree)

- ➡️ [Trie (Prefix Tree) Guide](https://hackmd.io/@siansiansu/B1qHrIPdR)

### Suffix Array and Suffix Tree

- 🟥 [1044\. Longest Duplicate Substring](https://leetcode.com/problems/longest-duplicate-substring/)

String Compression
------------------

- 🟨 [443\. String Compression](https://leetcode.com/problems/string-compression/)

Regular Expression
------------------

- 🟥 [10\. Regular Expression Matching](https://leetcode.com/problems/regular-expression-matching/)

Problem Difficulty Legend
-------------------------

- 🟩 Easy
- 🟨 Medium
- 🟧 Medium-Hard
- 🟥 Hard
- ⬛ Very Hard

Additional Resources
--------------------

- [String Algorithms (Video)](https://www.youtube.com/watch?v=3aGSqasVPsI)
- [KMP Algorithm Explained](https://www.geeksforgeeks.org/kmp-algorithm-for-pattern-searching/)
- [Trie Data Structure Tutorial](https://www.hackerearth.com/practice/data-structures/advanced-data-structures/trie-keyword-tree/tutorial/)