Herein is a high-performance solver for Apple News game Quartiles, written in Rust using the Ratatui text-based user interface (TUI) library.

There are two modes of operation: generate and solve. The mode is specified by eponymous subcommand.

In both modes, the application looks for an English dictionary in the directory specified via the -d option, which defaults to dict if unspecified. The name of the dictionary, sans the file extension, is specified via the -n option, which defaults to english if unspecified. If a binary dictionary (.dict) is present, then the application uses it; otherwise, the plaintext dictionary (.txt) is used instead, and an eponymous binary dictionary (.dict) is generated next to the plaintext one.

In generate mode, the application exits after performing the conversion.

In solve mode, the application opens the TUI:

The user may then fill in the Quartiles board by navigating among the cells. The following commands are available:

• Up arrow: Select the cell above.
• Right arrow: Select the cell to the right.
• Down arrow: Select the cell below.
• Left arrow: Select the cell to the left.
• Tab: Select the next cell, iterating left-to-right and wrapping to the beginning of the row below.
• Shift Tab: Select the previous cell, iterating right-to-left and wrapping to the end of the row above.
• Delete: Clear the selected cell.
• Shift Delete: Clear all cells.
• A, B, C, D, …, X, Y, Z: Append the corresponding letter to the selected cell.
• Backspace: Remove the last letter from the selected cell.
• Escape: Exit the program.
• Enter: Start the solver. Requires every cell to be populated. No effect if any cells remain empty.

After filling in a board, it should look something like this:

The user may then press Enter to launch the solver. The solver animates its traversal of the search space, highlighting valid words and adding them to the Solution:

While the solver is running, the user may press Escape to exit the program. When the solver completes, an indication of success or failure appears along the bottom edge of the Puzzle pane, and focus moves to the Solution pane.

The following commands are available:

• Up arrow: Select the word above. Deselects at the top edge.
• Down arrow: Select the word below. Deselects at the bottom edge.
• Escape: Exit the program.

After the TUI exits, the terminal is restored and the complete solution is written to standard output (unless the -q option is used).

$ cargo build --release

In generate mode:

$ cargo run --release generate

In solve mode:

$ cargo run --release solve

To display the main modes and general options:

at 21:36:01 ➜ cargo run --release -- --help
CLI for solving Quartiles puzzles

Usage: quartiles-solver [OPTIONS] <COMMAND>

Commands:
  generate  Just generate the binary dictionary and exit
  solve     Open the text-based user interface (TUI) for inputting and solving a Quartiles puzzle. The solution will be written to standard output
  help      Print this message or the help of the given subcommand(s)

Options:
  -d, --directory <DIRECTORY>    The path to the directory containing the dictionary files. Can be changed from the TUI [default: dict]
  -n, --dictionary <DICTIONARY>  The name of the dictionary. This is the name shared by the text and binary files, sans the extension. Can be changed from the TUI [default: english]
  -h, --help                     Print help
  -V, --version                  Print version

When running the application in generate mode, no special options are recognized.

When running the application in solve mode, the follow options are recognized:

at 21:35:21 ➜ cargo run --release solve --help
Open the text-based user interface (TUI) for inputting and solving a Quartiles
puzzle. The solution will be written to standard output

Usage: quartiles-solver solve [OPTIONS]

Options:
  -d, --highlight-duration <HIGHLIGHT_DURATION>
          How long (in µs) to highlight an individual word in the TUI [default: 400]
  -q, --quiet
          Suppress emission of the solution to standard output
  -h, --help
          Print help

$ cargo test

$ cargo bench

You can install the binary, quartiles-solver, so that it can be run without the project directory:

$ cargo install --path .

Be sure to copy the dictionary directory to its desired installation location. To use the installed binary, you will have to specify this location when running the application:

$ quartiles-solver -d /path/to/installed/directory

You must also specify -n if you renamed the dictionary files.