Strings - Volume 2 - C++ Edition

Stop memorizing string solutions. Start seeing why they work.

Strings - Volume 2 - C++ Edition teaches 51 string algorithms through plain-language explanations, C++ implementations, and step-by-step visual walkthroughs that trace the index, the window, and the stack through every step. Every algorithm is printed in clear grayscale, so characters, windows, and counts stand apart at a glance and are easy to trace.

Watch a string compress and rewrite itself in place. Follow a pattern as it slides across the text. See a trie grow one character at a time, and track a DP table as it measures the distance between two words. Instead of holding every changing index in your head, follow the execution on the page.

The visual walkthroughs use small multiples, a data visualization technique that presents successive stages of an algorithm as a series of consistently structured diagrams. By seeing meaningful stages together, you can compare states, follow what moves, and understand how each decision affects the next. This brings the algorithm to life, reinforcing understanding and helping the underlying patterns and mechanics stay with you longer.

Every main algorithm is presented in three complementary parts:

Understanding & Reasoning: Learn the goal, key idea, edge cases, and time and space complexity before studying the implementation.

Inspect & Debug: Examine C++ code alongside an AI-Era Interview Lens that challenges you to question assumptions, recognize plausible mistakes, and explain why a solution is correct.

Trace & Walkthrough: Follow the input through intermediate states to the result, with visual explanations of the decisions that matter.

The five core patterns cover Encoding, Compression & In-Place Manipulation; Pattern Matching; Tries, Dictionaries & Word Structures; DP: Subsequences & Edit Distance; and Conversion, Parsing & Math. Along the way you'll build real fluency in compressing and rewriting strings in place, then carry that same rigor into tries: building them, searching them, and using them to power autocomplete and word validation.

There's an old engineering joke: ask ten engineers to reverse a string and you'll get ten different one-liners. Ask them to build a trie from scratch and you'll find out who actually understands strings.

Every code sample was compiled, tested against edge cases beyond what's printed on the page, and independently reviewed before making it into the book.

Designed for readers with basic C++ knowledge who want to strengthen coding interview preparation, debugging, and algorithmic reasoning.

This is Volume 2 of the two-volume C++ Strings collection. All of its algorithms are also included in Strings - Complete Edition - C++ Edition.

Understand the idea. Follow the state. Explain the result.