Strings -- Map of Content

Map of Content for all pages derived from Strings (Character Hashing in C++).

Core Paradigm

Two-Phase Hashing Paradigm — the fundamental model
Hashing Store Phase (Phase 1) — building the frequency structure
Hashing Retrieval Phase (Phase 2) — querying the structure

Data Structures

Frequency Array — fixed-size array for known domains
Unordered Map for Frequency Counting — hash map for flexible domains
Direct Array Access — hardware-level O(1) array indexing
Hash Collision Overhead — performance cost of hash maps

Mappings & Conversions

Character-to-Index Mapping — ch - 'a'
Index-to-Character Conversion — i + 'a'
ASCII Math Elimination — maps remove the need for ASCII math

Key Properties & Assumptions

Known Range Assumption — when arrays work
Memory Efficiency of Frequency Array — fixed 104-byte footprint
Hash Map Flexibility — any hashable key type
Hash Map Traversal Method — iterating key-value pairs
Unordered Map Non-Determinism — unspecified iteration order

Problem Patterns (Phase 2)

Most Frequent Character via Hashing — traverse for max
First Non-Repeating Character via Hashing — re-traverse input
Anagram Detection via Hashing — compare two structures
Character Hashing Use Cases — catalog of all patterns

Decision Making

Array vs Hash Map Decision Framework — choosing the right tool
Frequency Array vs Hash Map — detailed comparison
Two-Phase Hashing Patterns — catalog of Phase 2 strategies

22 items under this folder.

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hashing