Problem 174. Roll the Dice!

Created by @bmtran (Bryant Tran)

Solve Later

{"relationships":[{"relationshipType":"http://schemas.mathworks.com/matlab/code/2013/relationships/document","targetMode":"","relationshipId":"rId1","target":"/matlab/document.xml"},{"relationshipType":"http://schemas.mathworks.com/matlab/code/2013/relationships/output","targetMode":"","relationshipId":"rId2","target":"/matlab/output.xml"}],"parts":[{"partUri":"/matlab/document.xml","relationship":[],"contentType":"application/vnd.mathworks.matlab.code.document+xml","content":"<?xml version=\"1.0\" encoding=\"UTF-8\"?>\n<w:document xmlns:w=\"http://schemas.openxmlformats.org/wordprocessingml/2006/main\"><w:body><w:p><w:pPr><w:pStyle w:val=\"text\"/></w:pPr><w:r><w:rPr><w:b/></w:rPr><w:t>Description</w:t></w:r></w:p><w:p><w:pPr><w:pStyle w:val=\"text\"/></w:pPr><w:r><w:t>Return two random integers between 1 and 6, inclusive, to simulate rolling 2 dice.</w:t></w:r></w:p><w:p><w:pPr><w:pStyle w:val=\"text\"/></w:pPr><w:r><w:rPr><w:b/></w:rPr><w:t>Example</w:t></w:r></w:p><w:p><w:pPr><w:pStyle w:val=\"code\"/></w:pPr><w:r><w:t><![CDATA[   [x1,x2] = rollDice();\n   x1 = 5;\n   x2 = 2;]]></w:t></w:r></w:p></w:body></w:document>"},{"partUri":"/matlab/output.xml","contentType":"text/xml","content":"<?xml version=\"1.0\" encoding=\"UTF-8\" standalone=\"no\" ?><embeddedOutputs><metaData><evaluationState>manual</evaluationState><layoutState>code</layoutState><outputStatus>ready</outputStatus></metaData><outputArray type=\"array\"/><regionArray type=\"array\"/></embeddedOutputs>"}]}

Solve

Solution Stats

12788 Solutions
5275 Solvers

Last Solution submitted on Oct 20, 2021

Last 200 Solutions

Problem Comments

17 Comments

17 Comments

Show 14 older comments

Sourav Mondal on 20 Nov 2012

is the solution correct???

Jonathan on 19 Nov 2014

To clarify the problem statement, it would be good to specify the dice are fair.

Dale Crawford on 7 Dec 2015

I've done something like this on an arduino for one of my classes

John D'Errico on 23 Aug 2016

The first test case for this problem is flat out statistically terrible! In fact, it is quite easy for that assertion to fail on a well defined set of uniform dice! So if you submitted a "valid" solution to this trivial problem, and it failed, then re-submit it. It may well succeed the second time you try, with no change to your function at all.

Alexander Kramlich on 14 Sep 2016

Use randi function instead of rand.

David Verrelli on 17 Oct 2017

Rigorous testing of RNG's is a challenging topic. See e.g. https://en.wikipedia.org/wiki/Diehard_tests and https://en.wikipedia.org/wiki/TestU01 .

jiangming wang on 10 Apr 2019

why can't use unidrnd(6)?

Oliver Warlow on 12 Apr 2019

Anyone want to tell me the odds of correctly completing the problem, and then having the checker reject it? Because i have a screenshot of my solution being rejected. Tried exactly the same again and it passed.

goc3 on 22 Apr 2019

@jiangming wang: Cody utilizes vanilla MATLAB (no toolboxes).

Sariha Azad on 7 Jun 2019

Someone please explain me the question

Le Manh Long Le Manh Long on 29 Sep 2019

Đề khó hiểu thật !

David Motson on 4 Nov 2019

I offered a solution that should be working (works okay in Matlab) but not here: round(rand()*5+1); - not the most optimum, but still provides the correct output, yet fails the test

Fakhteh Ghalami on 9 Nov 2019

can anyone help me why
x1 = 1 + (5)*rand(1,1);
x2 = 1 + (5)*rand(1,1);
is wrong???

Miriam Sánchez Fernández on 7 Nov 2020

It's very easy with function "randi"

Siddhartha Kosti on 23 Nov 2020

Yes, it is better to use randi, instead on rand

虎珀王 on 5 Oct 2021 at 2:25

rand generates random numbers and randi generates random integers

Deep Kasar on 17 Oct 2021 at 16:45

Very easy

Solution Comments

Solution 5671560

1 Comment

1 Comment

john perkins on 4 May 2021

simple!

Solution 4233725

1 Comment

1 Comment

E Cameron Renfrew on 13 Dec 2020

I really liked this problem...

Solution 3665938

Solution 3665763

1 Comment

1 Comment

Juan Sagarduy on 15 Nov 2020

a problem with the test suite. Due to the amount of random generation number, the server collapses. It would be nice to reduce 6000 to maybe 100. So that valid solutions (tested in MATLAB desktop) are accepted.

Solution 3602980

1 Comment

1 Comment

Swati on 10 Nov 2020

What's wrong with this solution? Can someone tell me?
function [x1,x2] = rollDice()
rng(0,'twister');
r=randperm(6,10)
x1 = r(1)
x2 =r(2)
end

Solution 2889740

1 Comment

1 Comment

Sanchita Malla on 29 Aug 2020

x1=randi(6,1);
x2=randi(6,1);

interesting

Solution 2823927

1 Comment

1 Comment

Abhijeet Deshmukh on 12 Aug 2020

Can I get the answer for this question

Solution 2586400

1 Comment

1 Comment

Piero Cimule on 20 Jun 2020

r = randi(6,[1,2])
x1 = r(1);
x2 = r(2);

Solution 1985875

2 Comments

2 Comments

Robin French on 22 Oct 2019

This failed on first submission, and completed successfully on second. Does this mean the test is non-robust?

Syed Shahed on 26 Apr 2020

the test case is totally erroneous.

Solution 1875872

1 Comment

1 Comment

lmehl on 16 Jul 2019

LOL. Just my luck.

Solution 311131

2 Comments

2 Comments

niko_k on 27 Aug 2013

solution is correct in my opinion.

Tim on 27 Aug 2013

rand(1,1)*5+1 will produce random numbers uniformly distributed between 1 and 6; round will convert values from 1 to 1.5 to 1, and values from 1.5 to 2.5 to 2, so 1 will occur only about half as often as 2. Overall, 1 and 6 will occur only about half as often as 2, 3, 4, and 5.

Solution 167407

1 Comment

1 Comment

Paul Peeling on 23 Nov 2012

my second ever pseudo random number generator (the first wasn't very random) http://en.wikipedia.org/wiki/Linear_congruential_generator

Solution 122564

2 Comments

2 Comments

Peter Wittenberg on 11 Aug 2012

This is not two random rolls. The second number will never match the first, so the statistical distribution is not correct, although the test suite is not sophisticated enough to catch it.

Matthew M. on 28 Aug 2012

^Agreed.

Solution 68395

1 Comment

1 Comment

Kye Taylor on 31 Mar 2012

Super rad test suite

Solution 46500

2 Comments

2 Comments

Giuseppe Cardillo on 20 Feb 2012

THIS SOLUTION IS CORRECT!!!!!

David Verrelli on 17 Oct 2017

Not correct. Same coding issue as in Solution 311131.

Solution 29002

2 Comments

2 Comments

Santiago Velasco-Forero on 2 Aug 2012

False solution.

David Verrelli on 17 Oct 2017

Agreed: this is not a genuine solution, although it does (sometimes) pass the current test as implemented.

Solution 15159

1 Comment

1 Comment

@bmtran (Bryant Tran) on 30 Jan 2012

Nice! didn't know about that function.

Problem Recent Solvers5275

Problem Tags

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!

Problem 174. Roll the Dice!

Solution Stats

Last 200 Solutions

Problem Comments

Solution Comments

Problem Recent Solvers5275

Suggested Problems

More from this Author56

Problem Tags

Community Treasure Hunt

Problem 174. Roll the Dice!

Solution Stats

Last 200 Solutions

Problem Comments

Solution Comments

Problem Recent Solvers5275

Suggested Problems

More from this Author56

Problem Tags

Community Treasure Hunt

Players