mersenneforum.org  

Go Back   mersenneforum.org > Fun Stuff > Puzzles

Reply
 
Thread Tools
Old 2017-08-30, 14:19   #1
R. Gerbicz
 
R. Gerbicz's Avatar
 
"Robert Gerbicz"
Oct 2005
Hungary

2×733 Posts
Default September 2017

The new Ibm puzzle is out: https://researchweb.watson.ibm.com/h...ember2017.html
R. Gerbicz is offline   Reply With Quote
Old 2017-08-30, 22:08   #2
science_man_88
 
science_man_88's Avatar
 
"Forget I exist"
Jul 2009
Dumbassville

26×131 Posts
Default

quite a few restrictions as I see it.
science_man_88 is offline   Reply With Quote
Old 2017-08-31, 13:26   #3
science_man_88
 
science_man_88's Avatar
 
"Forget I exist"
Jul 2009
Dumbassville

26×131 Posts
Default

for anyone wondering these restrictions include:

rook can't be within 2 of the king on the side being attacked, knight can't be 3 out from the king, bishop can't be 2 out from the king.
science_man_88 is offline   Reply With Quote
Old 2017-08-31, 13:31   #4
LaurV
Romulan Interpreter
 
LaurV's Avatar
 
Jun 2011
Thailand

5·1,889 Posts
Default

That is a nice one for hand practice! However, easy to program, and the search space is very small, only 960 positions, of each two moves (first is a pawn move), extremely small!

Most probably, skip.
(no time...)
LaurV is online now   Reply With Quote
Old 2017-08-31, 13:37   #5
LaurV
Romulan Interpreter
 
LaurV's Avatar
 
Jun 2011
Thailand

944510 Posts
Default

Quote:
Originally Posted by science_man_88 View Post
for anyone wondering these restrictions include:

rook can't be within 2 of the king on the side being attacked, knight can't be 3 out from the king, bishop can't be 2 out from the king.
That is not true, about horses, see how the starting positions are chosen using dices. The only restrictions are king between rooks and opposite-color bishops. Other (concerning castling, whatever) are not of any concern, because the game will not progress so much, you mate in two. And there is no need for spoilers when you talk about what position is valid, this is assumed known by hypothesis. There are 960 positions, that's all. You do not need to reinvent this part. You only need to say how many of these 960 allow a fool mate for either black or white.

Last fiddled with by LaurV on 2017-08-31 at 13:42
LaurV is online now   Reply With Quote
Old 2017-08-31, 13:47   #6
henryzz
Just call me Henry
 
henryzz's Avatar
 
"David"
Sep 2007
Cambridge (GMT/BST)

2×5×587 Posts
Default

Quote:
Originally Posted by LaurV View Post
That is a nice one for hand practice! However, easy to program, and the search space is very small, only 960 positions, of each two moves (first is a pawn move), extremely small!

Most probably, skip.
(no time...)
More time consuming programming than actually hard. I am thinking of doing it by hand.
henryzz is online now   Reply With Quote
Old 2017-08-31, 14:08   #7
science_man_88
 
science_man_88's Avatar
 
"Forget I exist"
Jul 2009
Dumbassville

100000110000002 Posts
Default

Quote:
Originally Posted by LaurV View Post
That is not true, about horses, see how the starting positions are chosen using dices. The only restrictions are king between rooks and opposite-color bishops. Other (concerning castling, whatever) are not of any concern, because the game will not progress so much, you mate in two. And there is no need for spoilers when you talk about what position is valid, this is assumed known by hypothesis. There are 960 positions, that's all. You do not need to reinvent this part. You only need to say how many of these 960 allow a fool mate for either black or white.
it isn't false about the knight laurv, if you have a knight 3 out from the king on the side being attacked it can block the queens attack.
science_man_88 is offline   Reply With Quote
Old 2017-08-31, 14:25   #8
LaurV
Romulan Interpreter
 
LaurV's Avatar
 
Jun 2011
Thailand

5×1,889 Posts
Default

aaa.. ok, now I understood what you want to say, and I understood why you used the spoiler, you actually were trying to solve the puzzle, but I though you were talking about restrictions when you set the initial position. However, that does not affect the result, if you do it by hand it just doesn't matter, and if you do it with a program, the program is not interested in these "restrictions", it just tries brute force, all possible combinations of two moves, from which one must be a pawn move (as well it can be the first, no matter if you start with a horse, you will still need to move a pawn to allow fool mate) and exits if a fool mate is found. The search space is very small.
LaurV is online now   Reply With Quote
Old 2017-08-31, 18:53   #9
henryzz
Just call me Henry
 
henryzz's Avatar
 
"David"
Sep 2007
Cambridge (GMT/BST)

2·5·587 Posts
Default

Quote:
Originally Posted by science_man_88 View Post
it isn't false about the knight laurv, if you have a knight 3 out from the king on the side being attacked it can block the queens attack.
Yes but can't white move a pawn on the first move and that knight on the second moving it out of reach.
Also, I can't see why fools mate needs to be the queen couldn't a bishop do a 2 move CM in 960
henryzz is online now   Reply With Quote
Old 2017-08-31, 20:25   #10
science_man_88
 
science_man_88's Avatar
 
"Forget I exist"
Jul 2009
Dumbassville

20C016 Posts
Default

Quote:
Originally Posted by henryzz View Post
Yes but can't white move a pawn on the first move and that knight on the second moving it out of reach.
Also, I can't see why fools mate needs to be the queen couldn't a bishop do a 2 move CM in 960
consistent definitions between variants ? in theory yes a bishop could in theory if it can be placed int he correct position without wrecking what else is needed to be avoided.
science_man_88 is offline   Reply With Quote
Old 2017-09-01, 05:47   #11
LaurV
Romulan Interpreter
 
LaurV's Avatar
 
Jun 2011
Thailand

5×1,889 Posts
Default

Quote:
Originally Posted by henryzz View Post
Yes but can't white move a pawn on the first move and that knight on the second moving it out of reach.
Also, I can't see why fools mate needs to be the queen couldn't a bishop do a 2 move CM in 960
You need to move both pawns, otherwise the second pawn blocks the mate, in most cases (except when the bishop/queen/whatever is on line 4). You still get a fool mate, but not in the minimal number of moves. In fact when you send the solution, you may need to specify like "x positions allow fool mate in 2, y positions allow fool mate in 3, z positions allow fool mate in 4", etc(up to you how high you want to go , because if they are not very specific about it, so it can be interpreted one way or the other.
LaurV is online now   Reply With Quote
Reply

Thread Tools


Similar Threads
Thread Thread Starter Forum Replies Last Post
September 2016 Batalov Puzzles 8 2016-10-04 14:10
September 2015 Xyzzy Puzzles 12 2015-10-07 14:43
September 2014 Xyzzy Puzzles 3 2014-11-02 19:04
TPS Record Rally: September 16-21 Oddball Twin Prime Search 11 2011-09-22 06:47
Anyone going to Vienna in September? fivemack Factoring 1 2007-09-07 00:29

All times are UTC. The time now is 05:18.

Tue May 11 05:18:35 UTC 2021 up 32 days, 23:59, 1 user, load averages: 1.58, 1.56, 1.76

Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2021, Jelsoft Enterprises Ltd.

This forum has received and complied with 0 (zero) government requests for information.

Permission is granted to copy, distribute and/or modify this document under the terms of the GNU Free Documentation License, Version 1.2 or any later version published by the Free Software Foundation.
A copy of the license is included in the FAQ.