Countdown Solver

A cross-platform desktop app that solves the two puzzle games from the UK TV show Countdown — handy at home, or for double-checking a contestant's working:

• Numbers — pick six numbers and a target between 100 and 999, and the solver finds an arithmetic expression (+ - x /, each number used at most once, no fractions or negative numbers along the way) that hits the target exactly, or gets as close as possible.
• Letters — pick nine letters, and the solver finds every valid word hiding in them, longest first.

There's a third game on the show, the Conundrum (unscramble nine letters into one word), which the app can generate and solve too.

Try it

Grab a build from the project's releases, or build it yourself — see Getting started. New to the app? How to play walks through each round and what the results mean.

A tour of the app

=== "Letters"

![Letters page](assets/screenshots/letters.png)

=== "Conundrum"

![Conundrum page](assets/screenshots/conundrum.png)

=== "Settings"

![Settings page](assets/screenshots/settings.png)

Under the hood

All the game logic lives in a small, dependency-free C++23 library, countdown::solver, with no GUI or platform code in sight — it's unit tested on its own and could be dropped into a different frontend entirely. A thin Qt 6 Quick (QML) app sits on top for the GUI you see above. See Architecture for the tour.

License

CountdownSolver is free and open source under the GPL-3.0-or-later license. Contributions are welcome — see Contributing.