mersenneforum.org  

Go Back   mersenneforum.org > Fun Stuff > Puzzles

Reply
 
Thread Tools
Old 2017-05-29, 16:42   #1
R. Gerbicz
 
R. Gerbicz's Avatar
 
"Robert Gerbicz"
Oct 2005
Hungary

26568 Posts
Default June 2017

There is a new Ibm puzzle:
https://www.research.ibm.com/haifa/p.../June2017.html
R. Gerbicz is offline   Reply With Quote
Old 2017-05-29, 20:23   #2
Batalov
 
Batalov's Avatar
 
"Serge"
Mar 2008
Phi(4,2^7658614+1)/2

5·1,877 Posts
Cool

Nice one! I think I have a "*" solution... (at least two)

Last fiddled with by Batalov on 2017-05-29 at 20:32 Reason: there is more than one
Batalov is offline   Reply With Quote
Old 2017-06-05, 21:37   #3
R. Gerbicz
 
R. Gerbicz's Avatar
 
"Robert Gerbicz"
Oct 2005
Hungary

5AE16 Posts
Default

There is an update:

"Update (5/6): Division by zero is not allowed, but you can use non integers and unary minus (like the example above); and you get a '*' for every prime solution."
R. Gerbicz is offline   Reply With Quote
Old 2017-06-05, 22:15   #4
Batalov
 
Batalov's Avatar
 
"Serge"
Mar 2008
Phi(4,2^7658614+1)/2

5·1,877 Posts
Default

Quote:
Originally Posted by R. Gerbicz View Post
There is an update:

"Update (5/6): Division by zero is not allowed, but you can use non integers and unary minus ..."
Instead of "non integers", he should have said "rationals". Or "fractions".
Or else we can do \(e^{i \pi}\) or something like \(\sqrt 4\).

Next month I am going to set up a webcrawler to watch the 'July2017.html' page
...so that I will not lose a couple hours to Robert ;-)

(This time I only learned of the problem launch from this thread.)
Batalov is offline   Reply With Quote
Old 2017-06-06, 00:53   #5
uau
 
Jan 2017

23·11 Posts
Default

Quote:
Originally Posted by Batalov View Post
Instead of "non integers", he should have said "rationals". Or "fractions".
Or else we can do \(e^{i \pi}\) or something like \(\sqrt 4\).
Not really. You can't insert arbitrary constants or operators into the expression (not integers or rationals either). The text only means that using the listed basic operators is allowed to create non-integer intermediate results (things like (1/3)*9 are allowed); allowing non-rational ones or not makes no difference as there are no operators which could create them.
uau is offline   Reply With Quote
Old 2017-06-06, 01:38   #6
science_man_88
 
science_man_88's Avatar
 
"Forget I exist"
Jul 2009
Dumbassville

26×131 Posts
Default

Quote:
Originally Posted by uau View Post
Not really. You can't insert arbitrary constants or operators into the expression (not integers or rationals either). The text only means that using the listed basic operators is allowed to create non-integer intermediate results (things like (1/3)*9 are allowed); allowing non-rational ones or not makes no difference as there are no operators which could create them.
then the term to use was rational. A non-integer includes the complement of the integers under the complex numbers etc.
science_man_88 is offline   Reply With Quote
Old 2017-06-06, 05:41   #7
LaurV
Romulan Interpreter
 
LaurV's Avatar
 
Jun 2011
Thailand

935810 Posts
Default

grrr... another silly problem... the formulation is unclear, where and whenever you can/may/must place signs, and what's happening if you don't...

"while other seven-digit numbers simply cannot be solved, such as 0314157"

0+3-1+41+57=100

skip.
LaurV is offline   Reply With Quote
Old 2017-06-06, 05:46   #8
uau
 
Jan 2017

23×11 Posts
Default

Quote:
Originally Posted by science_man_88 View Post
then the term to use was rational. A non-integer includes the complement of the integers under the complex numbers etc.
Nope. There is no limit to integers or any other particular class of intermediate results. Complex numbers would be allowed if the list of operators included any that produced them. Them being allowed just doesn't matter because there's no way to produce them.
uau is offline   Reply With Quote
Old 2017-06-06, 05:49   #9
uau
 
Jan 2017

23×11 Posts
Default

Quote:
Originally Posted by LaurV View Post
grrr... another silly problem... the formulation is unclear, where and whenever you can/may/must place signs, and what's happening if you don't...

"while other seven-digit numbers simply cannot be solved, such as 0314157"

0+3-1+41+57=100

skip.
I don't think it was unclear. Your "41 + 57" is quite clearly forbidden by the problem statement: "Without changing the order or concatenating two or more digits into a larger number".
uau is offline   Reply With Quote
Old 2017-06-06, 05:53   #10
Batalov
 
Batalov's Avatar
 
"Serge"
Mar 2008
Phi(4,2^7658614+1)/2

938510 Posts
Smile

Quote:
Originally Posted by LaurV View Post
grrr... another silly problem... the formulation is unclear, where and whenever you can/may/must place signs, and what's happening if you don't...

"while other seven-digit numbers simply cannot be solved, such as 0314157"

0+3-1+41+57=100

skip.
Well, that part he explained just fine --
Quote:
Without changing the order or concatenating two or more digits into a larger number, use the basic operations and parentheses so that the answer of the mathematical equation is exactly 100.
"Concatenating" is too long of a word? I though that you Romans invented this word, so it shouldn't be lost in translation for you?
Batalov is offline   Reply With Quote
Old 2017-06-06, 06:01   #11
LaurV
Romulan Interpreter
 
LaurV's Avatar
 
Jun 2011
Thailand

100100100011102 Posts
Default

Whoooops...

Too fast a reading... the concatenated solution just jumped on my eyes from between the rows during I was skimming the text... Haha...

Ok, I will look for a solution and send one... to make it up. It may take a while, our algorithms are always slower than yours...
LaurV is offline   Reply With Quote
Reply

Thread Tools


Similar Threads
Thread Thread Starter Forum Replies Last Post
June 2016 Xyzzy Puzzles 16 2016-07-07 02:51
June 2015 Batalov Puzzles 10 2015-07-07 14:59
LLRnet/PRPnet rally June 4th-6th gd_barnes No Prime Left Behind 61 2010-07-30 17:28
Max on the move: vacation June 28/30-July 4 mdettweiler No Prime Left Behind 8 2009-07-05 05:20
LLRnet server rally 400<k<1001 June 20-22 mdettweiler No Prime Left Behind 67 2008-06-23 15:32

All times are UTC. The time now is 04:33.

Sun Apr 11 04:33:28 UTC 2021 up 2 days, 23:14, 1 user, load averages: 2.72, 2.20, 2.03

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.