Problem 46028. Paint it black!

Created by Rafael S.T. Vieira

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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:hyperlink w:docLocation=\"https://en.wikipedia.org/wiki/Flood_fill\"><w:r><w:t>Flood fill</w:t></w:r></w:hyperlink><w:r><w:t> is the algorithm used by bucket-fill tools in many image editors. The idea is that all connected pixels with the input color should have it changed to an output color starting at a pixel P = (x,y). Your task is to implement this algorithm replacing all colors within some tolerance (distance) from the input color with black.</w:t></w:r></w:p><w:p><w:pPr><w:pStyle w:val=\"text\"/></w:pPr><w:r><w:t>For instance:</w:t></w:r></w:p><w:p><w:pPr><w:pStyle w:val=\"text\"/></w:pPr><w:r><w:t>if the input_color=9, tolerance = 0, and P=[1,1], then the following grayscale image,</w:t></w:r></w:p><w:p><w:pPr><w:pStyle w:val=\"code\"/></w:pPr><w:r><w:t><![CDATA[9 9 9 2 9\n9 9 9 2 9\n2 2 2 9 9 \n9 9 9 9 9]]></w:t></w:r></w:p><w:p><w:pPr><w:pStyle w:val=\"text\"/></w:pPr><w:r><w:t>becomes,</w:t></w:r></w:p><w:p><w:pPr><w:pStyle w:val=\"code\"/></w:pPr><w:r><w:t><![CDATA[0 0 0 2 9\n0 0 0 2 9\n2 2 2 9 9 \n9 9 9 9 9]]></w:t></w:r></w:p><w:p><w:pPr><w:pStyle w:val=\"text\"/></w:pPr><w:r><w:t>Assume that all pixels have</w:t></w:r><w:r><w:t> </w:t></w:r><w:hyperlink w:docLocation=\"https://en.wikipedia.org/wiki/Pixel_connectivity#4-connected\"><w:r><w:t>4-neighborhoods</w:t></w:r></w:hyperlink><w:r><w:t>. And use the</w:t></w:r><w:r><w:t> </w:t></w:r><w:hyperlink w:docLocation=\"https://en.wikipedia.org/wiki/Taxicab_geometry\"><w:r><w:t>Manhattan distance</w:t></w:r></w:hyperlink><w:r><w:t> to decide if a color, a 1xn vector, is within tolerance.</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>"}]}

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Last Solution submitted on Oct 18, 2020

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Jeremy Perez on 16 Sep 2020

Really fun. Anti-cheat is brilliant.

Rafael S.T. Vieira on 16 Oct 2020 at 21:48

Thank you, Jeremy. I'm glad you liked it.

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Problem 46028. Paint it black!

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Problem 46028. Paint it black!

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