155. OCR A Level (H446) SLR26 – 2.3 Implement merge sort

About this video

OCR Specification Reference
A Level 2.3.1f

The merge sort is one of four sorting algorithms students need to know for A Level exams. This video explains the merge sort technique.

Key questions:

- Can you successfully implement a merge sort using a high-level programming language of your choice?
- Do you understand how a merge sort works and can you trace its code to explain how it works?

00:00 Implementing a merge sort
00:06 Intro
00:11 Checklist
00:31 What is the merge sort algorithm?
01:11 What are the applications of a merge sort?
01:32 Visualising a merge sort
01:51 Merge sort pseudocode
02:43 Merge sort in simple-structured English
03:07 From simple-structured English to pseudocode
12:29 Merge sort coded in Python
31:16 Final thoughts
31:24 An alternative implementation using recursion in Python
32:04 Key questions
32:23 Essential algorithms for A Level Computer Science text book
33:27 Outro

Last updated: 28.07.26

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