Author: Heiner Marxen
Date: 10:11:13 03/25/04
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On March 24, 2004 at 19:02:03, Dieter Buerssner wrote: >On March 23, 2004 at 18:25:54, Anson T J wrote: > >>A game begins with 1.e4 and ends in the fifth move with knight takes rook mate. >>Reconstruct the game. >> >>[d]rnbqkbnr/pppppppp/8/8/4P3/8/PPPP1PPP/RNBQKBNR b KQkq e3 0 1 > >The problem has exactly 2 solutions (one is a simple transposition of the >other). I already indicated the second solution (besides the one, that was >mentioned in other followups) in another post. I also indicated, how I came to >the conclusion (with brute force search). I was not 100% sure, whether another >first move of black than Nf6 could yield in another transposition (I was pretty >sure, from thinking myself about it). So, additionally to the experiments I >mentioned in my other followup, I also did a perft(9), but disallowing Nf6 this >time (used a hash table for it). No other solutions were found. Because I >already did a "perft(8)" after Nf6 without hash tables (with an algorithm, that >will find all transpositions), there cannot be another solution. > >>Major kudos if you solve it yourself! > >Not really myself. Brain time: < 1/2 hour (rather easy when you intend to use a >fast tool for the brute force part), CPU time: ~3 hours to come to the >conclusion, perhaps another 2 hours wasted CPU time. Coding time: 20 minutes >(really small changes to already existing perft code). > >If anybody finds another solution, I will give a crate of beer (or a nice bottle >of wine, or something similar) to the first one. It would mean a horrible bug >(in my thinking and/or coding). Your program agrees with (a modified version of) Chest, so the dangers are relatively small ;-) >Regards, >Dieter Cheers, Heiner
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