Hit the space bar to scramble the tiles, and hit the Enter key to start solving. You can hit space or Enter at any time to stop the animation.

Ian Parberry,
"A Memory-Efficient Method for Fast Computation of Short 15-Puzzle Solutions",
*IEEE Transactions on Computational Intelligence and AI in Games*,
Vol. 7, No. 2, pp. 200-203, 2015.
[pdf from IEEEXplore]

My PhD student Josh Taylor translated my C++ into ActionScript and produced the Flash
animation below.
If you are on one of those devices that don't allow Flash, you'll have to content yourself
with the animated gifs in the next section.

Hit the space bar to scramble the tiles, and hit the Enter key to start solving. You can hit space or Enter at any time to stop the animation.

In the following animations, the left-hand board
shows the solution found by the greedy algorithm from
my 1995 paper,
while the right-hand board shows the much shorter solution found by the new algorithm.
### Greedy Algorithm 95 Moves, New Algorithm 65 Moves

### Greedy Algorithm 115 Moves, New Algorithm 67 Moves

### Greedy Algorithm 131 Moves, New Algorithm 75 Moves

A preliminary version of this paper
was published as
Technical Report LARC-2014-02,
Laboratory for Recreational Computing,
Department of Computer Science and Engineering, University of North Texas, April 2014.
[BibTeX, pdf]