juniorHash Tables
What is a Hash Function?
Updated Apr 28, 2026
Short answer
A function that converts an input (key) into a fixed-size integer value used as an index.
Deep explanation
Hash tables are fundamental for fast lookups. A function that converts an input (key) into a fixed-size integer value used as an index. By using a mathematical transformation, they bypass linear scanning required by arrays.
Real-world example
A dictionary or phonebook lookup.
Common mistakes
- Assuming hash tables are always O(1) without considering collision frequency.
Follow-up questions
- What happens if the table is too full?