Problem 2873. feeling VERY lucky?

Created by Alfonso Nieto-Castanon

Solve Later

Just like Matthew's problem 2793 and Edward's problem 2872 (guess the number that Cody is thinking) but now you must solve it in your first try.

Good luck!

note

despite appearances this problem does not require any hacking at all (nor even manipulation of random streams). Look at the testsuite for details and only submit your solution if you are confident that it will pass (you do have only one chance)

hint

The solution to this problem has been posted over 10,000 times in Cody

Solve

Solution Stats

93 Solutions
20 Solvers

Last Solution submitted on Apr 08, 2020

Last 200 Solutions

Problem Comments

3 Comments

3 Comments

Jean-Marie Sainthillier on 24 Jan 2015

Hello Alfonso. It's a pleasure to see you again. An idea why my Solution 548586 doesn't pass the test in Problem 2793 ?

Alfonso Nieto-Castanon on 25 Jan 2015

Hi Jean-Marie, thanks, it is a pleasure to be back! In my opinion that does not work simply because the Matlab session where your solution is being evaluated is not a "clean" (just started) matlab session. Rather the testsuite will be evaluated by one of several Matlab servers available at any given timepoint, and while the variable space is cleared, and the directory structure is deleted before each evaluation there are many other properties (like the state of random streams, functions in memory, etc.) which are not reinitialized and will be influenced by the particular server's history of evaluated solutions (e.g. this is what allows hacks like freepass to work)

Alfonso Nieto-Castanon on 26 Jan 2015

edit: Sylvain solution here shows that I was wrong above, and the random seeds *are* reinitialized before running the testsuite, only that not to their 'default' state but rather likely by using rng('shuffle') (I have to look through Cody code to see if I can confirm this but that would be consistent with the observed behavior)

Solution Comments

Solution 1201815

1 Comment

1 Comment

Tom Holz on 31 May 2017

With apologies for the hack. The proper solutions are more elegant.

Solution 599597

1 Comment

1 Comment

goc3 on 20 Mar 2015

I'm confused why this works on my local version of Matlab but not the Cody server version?

Solution 567492

1 Comment

1 Comment

J.R.! Menzinger on 28 Jan 2015

Thanks Alfnoso for the comment... ;-)

Solution 566636

2 Comments

2 Comments

Alfonso Nieto-Castanon on 27 Jan 2015

this would count as a hack, but just because it is original a hint (if I am interpreting correctly): right idea wrong slash

J.R.! Menzinger on 28 Jan 2015

Yes, it was a try...
Oh! I forgot that the Cody servers run under linux... ;-)

Solution 565376

3 Comments

3 Comments

Alfonso Nieto-Castanon on 26 Jan 2015

ha, that would also work :)

J.R.! Menzinger on 27 Jan 2015

O_o but... why????

Guillaume on 27 Jan 2015

At the risk of giving the game away, go read the documentation of if.

Problem Recent Solvers20

Problem Tags

lucky guess