Start State:
Represented as: 1 5 2 3 0 6 10 7 4 8 9 11 12 13 14 15
Solved State:
Represented as: 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
This is obviously an easy example. We solve challenging board positions using IDA* and BTS. IDA* or iterative deepening A* is good if the cost of moving a tile is uniform (say 1). It fails when the cost of moving a tile is non-uniform. For example if cost of moving tile t is (t + 2) / (t + 1). In this case, tile 2 will cost 4/3 and tile 3 will cost 5/4. BTS or budgeted tree search can solve the sliding tile puzzle for non-uniform costs.
https://webdocs.cs.ualberta.ca/~nathanst/papers/sturtevant2020btsguide.pdf
Commands to test using C++:
mkdir build;cd build
cmake ..
make
./658_A1 "1 5 2 3 0 6 10 7 4 8 9 11 12 13 14 15"