An iOS app that solves the Huarong Pass sliding block puzzle, written in Swift.
Some history about the puzzle (most commonly known as Klotski in the West):
The app uses the breadth-first search algorithm to find the optimal solution to the puzzle i.e. the fewest steps required for the main piece (Cao Cao) to reach the exit. It is also guaranteed to find a solution if there is one. If there are other solutions with the same amounts of steps, it just shows one of them.
It also makes use of Zobrist hashing to represent the state of the board and to compute all the possible moves for the next boards. It is what yields the incredible performance of this app. (0.666s last time I tested on my Macbook for the standard board :])
You can test the app either on the Xcode Simulator or by installing it on your iPhone/iPad through Xcode.
- Choose the standard board or make your own custom board by adding/removing pieces from the board
- Count two-block moves in different directions as one step (leads to the 81-step solution for the standard board) or count two-block moves in the same direction only as one step (leads to a 91-step solution for the standard board)
- Start and cancel the solving execution, which happens on a background thread
- Step through all the board configurations in the optimal solution
| The standard board | The custom board | The custom board with selected pieces | The final step of the solution to the standard board |
|---|---|---|---|
 |
 |
 |
 |
- Play the game by sliding the puzzle pieces
- If you're stuck, show the next move as a hint, or if you give up, show the solution
- Add more preset boards, ranked by difficulty level (amount of steps it takes)
- Generate random boards and rank them by difficulty
- Different board sizes, piece sizes/shapes and exit(s)
- Yongsi Chen for the Chinese translation <3
- Yong Su for the inspiration about the Zobrist hashes
- chinesepuzzles.org for the wooden board image