Problem 924. intersection of matrices

Created by Richard

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Given two matrices filled with ones and zeros, determine if they share a common row, column entry. These matrices are of identical size.Examples:<pre class="language-matlab">Inputs A = [1 0 0 0 0
 0 1 0 0 0
 0 0 1 0 0
 0 0 0 1 0
 0 0 0 0 1 ] 
</pre><pre> and B = [0 1 0 0 0
 0 0 1 0 0
 0 0 0 1 0
 0 0 0 0 1
 1 0 0 0 0 ]</pre><pre class="language-matlab">Output tf is false
</pre><pre class="language-matlab">Inputs A = [1 1 1 0 1
 1 1 1 1 0
 0 1 1 1 1
 1 0 1 1 1
 1 1 0 1 1 ]
 and B = [0 1 0 0 0
 1 0 0 0 0
 0 0 0 0 1
 0 0 0 1 0
 0 0 1 0 0]
</pre>Output tf is true

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1034 Solutions
349 Solvers

Last Solution submitted on Jan 26, 2021

Last 200 Solutions

Problem Comments

6 Comments

6 Comments

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Marcel on 31 Dec 2013

I guess zeros are not included as common elements.

Elmar Zander on 3 Mar 2017

Yes. Seems to be a somewhat "ill-posed" problem...

Andrew Newell on 18 Apr 2017

What does "they share a common row, column entry" mean?

Nanfei Cheng on 23 Sep 2020

I think it should be a non-zero common row, column entry.

Chien-Han Su on 4 Nov 2020

Just consider the problem to be "Is there any i, j such that A(i,j) == B(i,j) == 1"

Jeong Suong Yang on 9 Nov 2020

I guess it means intersection of arrays, literally.

Solution Comments

Solution 4621039

1 Comment

1 Comment

Qin-Yong on 19 Jan 2021 at 5:50

tf=any(ismember([A(:)==1 B(:)==1],[1 1],'rows'));

Solution 2984500

Solution 1302071

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1 Comment

Li Ding on 19 Oct 2017

Re-wording is needed for this problem. Here is how I interpreted the problem:
1. "common row, column entry" means a same value at the same row-column location
2. zeros don't count. You need to check for non-zeros...

Problem Recent Solvers349

Problem Tags

matrix poor_problem_statement

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