Simple Sudoku solver, written in C#, and exposed as a function HTTP endpoint.

This web application is written in Angular 8, with an Azure Functions API, and no backend.
The underlying libraries are written in C#, with minimal external dependency.
When complete, this application should run as a static website in Azure Storage, with
a consumption-plan based API/backend.

This creates a stack which can host the website at the egress rate of Storage, for less
than ~$10/mo. Here, we are relying on functions automated scaling to manage the large CPU
requirement of this process. Additionally, AppInsights is used as the primary troubleshooting
and perf-tracking service.

This repo also defines an ARM (Azure Resource Manager) template, which can be used to provision
services in Azure, with the appropriate settings and nomenclature.

Currently, projects include:

• SudokuSolver.Solver

This is a C# class library, based on .NET Core 3.0, which takes a sudoku puzzle, as either
a string, or a 2D sbyte-array, and calculates the solution, if possible. For performance
reasons, a minumum of 17 clues (solved cells in the initial configuration) is required for
a puzzle to be solved. This is also the minimum number of clues required to imply a unique
solution to a Sudoku puzzle (McGuire, Tugemann, Civario) ^[1][2]

• SudokuSolverApp

This is an Angular 8 application, written using VS Code, allowing a user to manually enter
a Sudoku puzzle, and retrieve a solution. This app uses prebuilt Angular themes, and minimal
external dependencies, to facilitate learning. When complete, this application is hosted in
Azure Storage, as a static website. This is likely the cheapest possible way to host an Angular
app in Azure.

• SudokuSolver.Function

This is an Azure Functions project, which serves as an API for the Angular application. This
function currently defines a single endpoint.

GET /SolveSudoku/

This endpoint requires the Sudoku puzzle, serialized as a single string, be passed in as the
body of the HTTP request. The response will be of the shape:

{
    "Success": "Boolean value indicating whether this request was successfully fulfilled",
    "Message": "String value describing the result",
    "Result": "String value containing similarly serialized and corresponding Sudoku solution, if possible"
}

• SudokuSolver.Test

This is an Xunit unit-test project for SudokuSolver.Solver and SudokuSolver.Function. This
collection of unit tests includes a number of test puzzzles of varying complexity to test
efficacy, as well as invalid puzzles, unsolvable puzzles, known solutions, and faculties to
test all methods and endpoints with these. This project also tests the API endpoint, using
the same puzzles, asserting varying underlying results.