Crate Pusher

Goal

You are a warehouse worker: store all the crates on the glowing targets of the warehouse. The puzzle is solved as soon as every target holds a crate.

Rules

• You move one square at a time, horizontally or vertically.
• You can push a crate by walking into it, if the square behind it is free.
• You can never pull a crate, nor push two at once.

Controls

• Keyboard: arrow keys or W A S D to walk and push, U or Backspace to undo, R to restart, H for a hint.
• Swipe: one step (or push) in the direction of the gesture.
• Tap a square: the worker walks there by the shortest path.
• Tap a crate: its possible destinations light up; tap one and the crate is pushed there automatically.

Puzzles and generated warehouses

The 30 puzzles are original layouts drawn for this game; for each one, the hardest starting position was calculated by an exhaustive backward search. Each difficulty level groups six puzzles. The generated warehouses are built by reverse pulling: starting from the stored crates, the generator “pulls” the crates backwards, which guarantees a solution, and keeps the position that requires the most pushes.

About the AI

The solver is an A* search over pushes: it estimates the remaining work by an optimal matching of crates to targets (the Hungarian algorithm), prunes blocked positions (dead squares, frozen blocks, full squares) and merges equivalent positions of the worker. It finds the solution that needs the fewest pushes. The hint shows the next push of that solution and the path to get there; if the position has become unsolvable, it tells you how many pushes to undo.

Records (pushes, steps and time) are only recognised without hints or AI help.