Essential algorithms for GCSE and A Level Computer Science

Searching algorithms

Routines that find data within a data structure.

What is a hash table search?

The goal with a hash table is to immediately find an item in a sorted or unsorted list without the need to compare other items in the data set.  It is how programming languages implement a dictionary data structure.  A hashing function is used to calculate the position of an item in a hash table.

Hash table videos

What extra is in the book?

This algorithm / data structure has its own dedicated chapter in the book, which includes:

  1. Overview
  2. Typical applications / uses
  3. Typical operations
  4. The algorithm written out in simple-structured English
  5. The algorithm written out in pseudocode
  6. Full code listing Python
  7. Full code listing in Visual Basic
  8. Diagrammatic walk-through
  9. Efficiency discussion with reference to Big-O notation

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