Overview

This section covers interview problems focused on string manipulation, hashing techniques, and pattern matching.

Problem	Level	Key Concepts
Apply Refactor to Source Code	L3-L5	Offset-based text replacements, sorting, overlap detection
Transform a C-Style String	L3-L4	In-place string manipulation, two-pass forward/backward technique
Implement Swype Keyboard	L3-L4	Subsequence matching, dictionary lookup, Trie optimization
Best Anagram Finder	L3-L4	Anagram hashing, precomputation, group-by pattern
Find Buddies in Strings	L3-L4	Caesar-shift normalization, modular arithmetic, grouping
Contained Characters in a Grouped String	L3-L4	Streaming algorithms, group boundary detection, sliding window
Find Strings with a Given Prefix	L4	Binary search on sorted strings, Trie with subtree counts