Problem 45230. Remove duplicated triangles

Created by Nicolas Douillet

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{"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:t>Input T is a triangulation (triplet list of indices -positive integers-, each index refering to a vertex number in a corresponding vertices list).</w:t></w:r></w:p><w:p><w:pPr><w:pStyle w:val=\"text\"/></w:pPr><w:r><w:t>It sometimes happens a triangle may be duplicated several times. The goal of this problem is to remove all the duplicated triangles of T, and to keep only one.</w:t></w:r></w:p><w:p><w:pPr><w:pStyle w:val=\"text\"/></w:pPr><w:r><w:t>For instance if :</w:t></w:r></w:p><w:p><w:pPr><w:pStyle w:val=\"code\"/></w:pPr><w:r><w:t><![CDATA[T_in = [1 2 3;...\n 4 5 6;...\n 1 2 3;...\n 7 8 9;...\n 6 4 5;...\n 10 11 12;...\n 2 1 3;...\n 8 7 9;...\n 10 11 12]]]></w:t></w:r></w:p><w:p><w:pPr><w:pStyle w:val=\"text\"/></w:pPr><w:r><w:t>then the output must be :</w:t></w:r></w:p><w:p><w:pPr><w:pStyle w:val=\"code\"/></w:pPr><w:r><w:t><![CDATA[T_out = [1 2 3;...\n 4 5 6;...\n 7 8 9;...\n 10 11 12]]]></w:t></w:r></w:p><w:p><w:pPr><w:pStyle w:val=\"text\"/></w:pPr><w:r><w:t>since rows [1 2 3], [6 4 5], [2 1 3], [8 7 9], and [10 11 12] are just duplicata. Indeed triangle [i2 i1 i3] is the same as triangle [i1 i2 i3] for example.</w:t></w:r></w:p><w:p><w:pPr><w:pStyle w:val=\"text\"/></w:pPr><w:r><w:t>Hypothesis :</w:t></w:r></w:p><w:p><w:pPr><w:pStyle w:val=\"ListParagraph\"/><w:numPr><w:numId w:val=\"1\"/></w:numPr></w:pPr><w:r><w:rPr><w:b/></w:rPr><w:t>T is always a N x 3 integer matrix with N &gt; 0 (non empty matrix)</w:t></w:r></w:p><w:p><w:pPr><w:pStyle w:val=\"ListParagraph\"/><w:numPr><w:numId w:val=\"1\"/></w:numPr></w:pPr><w:r><w:t>Each row / triangle of T always contains three distinct integers</w:t></w:r></w:p><w:p><w:pPr><w:pStyle w:val=\"text\"/></w:pPr><w:r><w:t>Good work Matlab bro ! :)</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>"}]}

Input T is a triangulation (triplet list of indices -positive integers-, each index refering to a vertex number in a corresponding vertices list).It sometimes happens a triangle may be duplicated several times. The goal of this problem is to remove all the duplicated triangles of T, and to keep only one.For instance if :<pre class="language-matlab">T_in = [1 2 3;...
 4 5 6;...
 1 2 3;...
 7 8 9;...
 6 4 5;...
 10 11 12;...
 2 1 3;...
 8 7 9;...
 10 11 12]
</pre>then the output must be :<pre class="language-matlab">T_out = [1 2 3;...
 4 5 6;...
 7 8 9;...
 10 11 12]
</pre>since rows [1 2 3], [6 4 5], [2 1 3], [8 7 9], and [10 11 12] are just duplicata. Indeed triangle [i2 i1 i3] is the same as triangle [i1 i2 i3] for example.Hypothesis :<ul><li>T is always a N x 3 integer matrix with N &gt; 0 (non empty matrix)</li><li>Each row / triangle of T always contains three distinct integers</li></ul>Good work Matlab bro ! :)

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Last Solution submitted on Sep 12, 2020

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3d duplicat edge find geometry index indices mathematics mesh mesh processing surface triangle triangulation trimesh triplet vertex vertices

Problem 45230. Remove duplicated triangles

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Problem 45230. Remove duplicated triangles

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