How to programmatically solve the 15 (moving numbers) puzzle?

Question

all of you have probably seen the moving number/picture puzzle. The one where you have numbers from 1 to 15 in a 4x4 grid, and are trying to get them from random starting positi

Answer 1

I think The most effective way of solving this, is using additive patterns, with an admisible heuristic, and IDA* algorithm. As described here - http://www.aaai.org/Papers/JAIR/Vol22/JAIR-2209.pdf. (I think Felner told us he found a way which is quite better, but I don't remember exactly what it was (bidirectional A*?), but anyhow this should be sufficient (-: ).
Anyhow this course was long ago, so I recommend reading the article..
HTH. Take care.