Problem 52. What is the next step in Conway's Life?

Created by Cody Team

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Given a matrix A that represents the state of Conway's game of Life at one instant (time t=n), return the matrix B that represents the state of the game at the next instant (time t=n+1).

Assume a toroidal game board, so the edges of the matrix wrap left to right and top to bottom.

Examples:

 Input  A = [ 1   1   0   0
              0   1   0   0
              1   1   0   0
              0   0   0   0 ]

 Output B = [ 1   1   0   0
              0   0   1   0
              1   1   0   0
              0   0   0   0 ]

 Input  A = [ 0   1   1   0
              1   1   1   0
              0   0   1   0
              0   0   0   0 ]

 Output B = [ 1   0   1   1
              1   0   0   0
              0   0   1   1
              0   1   1   0 ]

Solve

Solution Stats

1440 Solutions
432 Solvers

Last Solution submitted on Jan 23, 2020

Last 200 Solutions

Problem Comments

5 Comments

5 Comments

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David Young on 5 Feb 2012

I think test sets should be designed to encourage general solutions. At present, the test set only has square boards - some more varied examples would make solvers seek code that is general.

mItk on 17 Oct 2016

Is there something wrong with the test suite? function B = life(A) B = A; end produces "Error using life Too many output arguments." See comment on solution 1019804.

mItk on 17 Oct 2016

I suppose the error "Error using life Too many output arguments." is due to shadowing. It seems thet test suite calls \toolbox\matlab\demos\life.m

shahriar memaran on 9 Mar 2017

I had so much fun with this problem. Thank you.

David Verrelli on 7 Feb 2018

Is there a syntax flaw in the Test Suite? Currently the first test displays with a first line of "%%A = [ ...", and in my solution (S 1435695) only the second test is displayed. Although apparently the first test is still being called (S 1435709)?

Solution Comments

Solution 1019804

1 Comment

1 Comment

mItk on 17 Oct 2016

Is there something wrong with the test suite?

function B = life(A)
B = A;
end

produces "Error using life Too many output arguments."

Solution 598431

1 Comment

1 Comment

Alison on 18 Mar 2015

This solution is for only a 4x4 A. See Solution 598430 for general solution.

Solution 598430

1 Comment

1 Comment

Alison on 18 Mar 2015

This is the solution for A of any size.

Solution 144659

1 Comment

1 Comment

Nicholas Howe on 5 Oct 2012

Ties the current leader in size, but works on all board sizes.

Solution 61610

1 Comment

1 Comment

Cris Luengo on 14 Jul 2012

This stops working if the input is not 4x4.

Solution 30146

1 Comment

1 Comment

Peter Wittenberg on 2 Apr 2012

Nice way of expanding A for circular convolution

Solution 29999

1 Comment

1 Comment

David Young on 5 Feb 2012

Humph! Solution 2234 uses imfilter, but this fails with imfilter not found!

Solution 29957

1 Comment

1 Comment

David Young on 5 Feb 2012

Nice - but only works for 4x4 boards.

Solution 29512

1 Comment

1 Comment

David Young on 5 Feb 2012

Puzzling - solution 2231 uses imfilter but this solution fails because padarray isn't available. Both are in the IPT.

Solution 14719

2 Comments

2 Comments

Peter Wittenberg on 2 Apr 2012

Nice usage of a simpler matrix for convolution (ones(3)) and readjustment of the logical conditions.

lkjslkjdlk on 23 Sep 2013

Good job!

Solution 2231

3 Comments

3 Comments

Peter Wittenberg on 2 Apr 2012

I was looking for a command to do a circular convolution, but couldn't figure it out. This is useful to learn and, I guess, the whole point of Cody

Martijn on 6 Jun 2015

However, learning is severely hindered by not being able to view solutions of smaller size. At least, as far as i know, this is not possible.

David Verrelli on 7 Feb 2018

_All_ solutions in this Problem will become viewable after you solve _another_ Problem in the same category (which here is "Cody Challenge").

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Problem 52. What is the next step in Conway's Life?

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Problem 52. What is the next step in Conway's Life?

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