What is it
An algorithm is a precise, step-by-step set of instructions for solving a problem or completing a task — the same idea whether it's a recipe, directions, or a piece of code.
Why it matters
Every program starts as an algorithm before it becomes code. At GCSE you'll describe algorithms with flowcharts and pseudocode, and compare standard ones — bubble sort, merge sort, binary search — by efficiency.
Exam tip
When comparing algorithm efficiency, examiners want reasoning in plain English — 'binary search halves the list each time, so it's much faster on large data' scores better than reciting a definition.
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