# QC2.9 Shor's Algorithm (Overview)

This skill introduces Shor's algorithm as a landmark quantum algorithm for integer factorisation, highlighting its conceptual components without requiring a full description. Learners study how Quantum Phase Estimation and modular arithmetic are combined to factor large numbers efficiently and why this constitutes an exponential speedup over classical algorithms. Emphasis is placed on understanding the high-level structure and role of quantum subroutines rather than performing detailed calculations.

## Requirements

* [[skill-tree:qc:1:3:b]]
* [[skill-tree:qc:2:8:b]]

## Learning Outcomes

* Describe the problem addressed by Shor's algorithm and its significance in quantum computation.
* Explain the high-level structure of Shor's algorithm, including the use of Quantum Phase Estimation and modular arithmetic.
* Compare the expected computational complexity of Shor's algorithm with classical factorisation approaches at a high level.