{"group":{"id":1,"name":"Community","lockable":false,"created_at":"2012-01-18T18:02:15.000Z","updated_at":"2026-04-06T14:01:22.000Z","description":"Problems submitted by members of the MATLAB Central community.","is_default":true,"created_by":161519,"badge_id":null,"featured":false,"trending":false,"solution_count_in_trending_period":0,"trending_last_calculated":"2026-04-06T00:00:00.000Z","image_id":null,"published":true,"community_created":false,"status_id":2,"is_default_group_for_player":false,"deleted_by":null,"deleted_at":null,"restored_by":null,"restored_at":null,"description_opc":null,"description_html":null,"published_at":null},"problems":[{"id":47508,"title":"Convert sorting indices to ranks","description":null,"description_html":"\u003cdiv style = \"text-align: start; line-height: 20.44px; min-height: 0px; white-space: normal; color: rgb(0, 0, 0); font-family: Menlo, Monaco, Consolas, monospace; font-style: normal; font-size: 14px; font-weight: 400; text-decoration: none solid rgb(0, 0, 0); white-space: normal; \"\u003e\u003cdiv style=\"block-size: 93px; display: block; min-width: 0px; padding-block-start: 0px; padding-top: 0px; perspective-origin: 407px 46.5px; transform-origin: 407px 46.5px; vertical-align: baseline; \"\u003e\u003cdiv style=\"block-size: 63px; font-family: Helvetica, Arial, sans-serif; line-height: 21px; margin-block-end: 9px; margin-block-start: 2px; margin-bottom: 9px; margin-inline-end: 10px; margin-inline-start: 4px; margin-left: 4px; margin-right: 10px; margin-top: 2px; perspective-origin: 384px 31.5px; text-align: left; transform-origin: 384px 31.5px; white-space: pre-wrap; margin-left: 4px; margin-top: 2px; margin-bottom: 9px; margin-right: 10px; \"\u003e\u003cspan style=\"block-size: auto; display: inline; margin-block-end: 0px; margin-block-start: 0px; margin-bottom: 0px; margin-inline-end: 0px; margin-inline-start: 0px; margin-left: 0px; margin-right: 0px; margin-top: 0px; perspective-origin: 0px 0px; transform-origin: 0px 0px; \"\u003e\u003cspan style=\"\"\u003eThe second output of sort() is the sorting index vector, telling where the corresponding element in the sorted vector was in the raw vector. However sometimes we want to know where the elements of the raw vector goes into the sorted vector, i.e., ranks.\u003c/span\u003e\u003c/span\u003e\u003c/div\u003e\u003cdiv style=\"block-size: 21px; font-family: Helvetica, Arial, sans-serif; line-height: 21px; margin-block-end: 9px; margin-block-start: 2px; margin-bottom: 9px; margin-inline-end: 10px; margin-inline-start: 4px; margin-left: 4px; margin-right: 10px; margin-top: 2px; perspective-origin: 384px 10.5px; text-align: left; transform-origin: 384px 10.5px; white-space: pre-wrap; margin-left: 4px; margin-top: 2px; margin-bottom: 9px; margin-right: 10px; \"\u003e\u003cspan style=\"block-size: auto; display: inline; margin-block-end: 0px; margin-block-start: 0px; margin-bottom: 0px; margin-inline-end: 0px; margin-inline-start: 0px; margin-left: 0px; margin-right: 0px; margin-top: 0px; perspective-origin: 0px 0px; transform-origin: 0px 0px; \"\u003e\u003cspan style=\"\"\u003eCan you find the shortest solution?\u003c/span\u003e\u003c/span\u003e\u003c/div\u003e\u003c/div\u003e\u003c/div\u003e","function_template":"function Ranks = SortingIndices2Ranks(SortingIndices)\r\n  Ranks=SortingIndices;\r\nend","test_suite":"%%\r\nRawVector=rand(10,1);\r\n[SortedVector,SortingIndices]=sort(RawVector);\r\nRanks=SortingIndices2Ranks(SortingIndices);\r\nassert(isequal(SortedVector(Ranks),RawVector));","published":true,"deleted":false,"likes_count":1,"comments_count":0,"created_by":362068,"edited_by":null,"edited_at":null,"deleted_by":null,"deleted_at":null,"solvers_count":13,"test_suite_updated_at":null,"rescore_all_solutions":false,"group_id":1,"created_at":"2020-11-15T04:05:17.000Z","updated_at":"2025-11-28T17:59:25.000Z","published_at":"2020-11-15T04:05:17.000Z","restored_at":null,"restored_by":null,"spam":false,"simulink":false,"admin_reviewed":false,"description_opc":"{\"parts\":[{\"partUri\":\"/matlab/document.xml\",\"contentType\":\"application/vnd.mathworks.matlab.code.document+xml\",\"content\":\"\u003c?xml version=\\\"1.0\\\" encoding=\\\"UTF-8\\\"?\u003e\u003cw:document xmlns:w=\\\"http://schemas.openxmlformats.org/wordprocessingml/2006/main\\\"\u003e\u003cw:body\u003e\u003cw:p\u003e\u003cw:pPr\u003e\u003cw:pStyle w:val=\\\"text\\\"/\u003e\u003cw:jc w:val=\\\"left\\\"/\u003e\u003c/w:pPr\u003e\u003cw:r\u003e\u003cw:t\u003eThe second output of sort() is the sorting index vector, telling where the corresponding element in the sorted vector was in the raw vector. However sometimes we want to know where the elements of the raw vector goes into the sorted vector, i.e., ranks.\u003c/w:t\u003e\u003c/w:r\u003e\u003c/w:p\u003e\u003cw:p\u003e\u003cw:pPr\u003e\u003cw:pStyle w:val=\\\"text\\\"/\u003e\u003cw:jc w:val=\\\"left\\\"/\u003e\u003c/w:pPr\u003e\u003cw:r\u003e\u003cw:t\u003eCan you find the shortest solution?\u003c/w:t\u003e\u003c/w:r\u003e\u003c/w:p\u003e\u003c/w:body\u003e\u003c/w:document\u003e\",\"relationship\":null}],\"relationships\":[{\"relationshipType\":\"http://schemas.mathworks.com/matlab/code/2013/relationships/document\",\"target\":\"/matlab/document.xml\",\"relationshipId\":\"rId1\"}]}"},{"id":1134,"title":"Get ranks of values in a vector","description":"For a given vector, say [6 3 8 2], return the ranks (ascending) of observations, i.e. [3 2 4 1]. Do not worry about tied ranks. If ties exist, what comes first takes the lower rank, e.g., [1 1 3] returns [1 2 3]. More exact treatment of ties will follow. No toolbox functions please!","description_html":"\u003cp\u003eFor a given vector, say [6 3 8 2], return the ranks (ascending) of observations, i.e. [3 2 4 1]. Do not worry about tied ranks. If ties exist, what comes first takes the lower rank, e.g., [1 1 3] returns [1 2 3]. More exact treatment of ties will follow. No toolbox functions please!\u003c/p\u003e","function_template":"function y = getrank(x)\r\n  y = x;\r\nend","test_suite":"%%\r\nx = 0:9;\r\ny_correct = 1:10;\r\nassert(isequal(getrank(x),y_correct))\r\n%%\r\nx = 9:-1:0;\r\ny_correct = 10:-1:1;\r\nassert(isequal(getrank(x),y_correct))\r\n%%\r\nx = [.5 .8 .1 .9 .7];\r\ny_correct = [2 4 1 5 3];\r\nassert(isequal(getrank(x),y_correct))\r\n%%\r\nx = [2 -1 7 -6 3 2];\r\ny_correct = [3 2 6 1 5 4] ;\r\nassert(isequal(getrank(x),y_correct))","published":true,"deleted":false,"likes_count":2,"comments_count":0,"created_by":3399,"edited_by":null,"edited_at":null,"deleted_by":null,"deleted_at":null,"solvers_count":57,"test_suite_updated_at":null,"rescore_all_solutions":false,"group_id":1,"created_at":"2012-12-24T13:01:10.000Z","updated_at":"2025-12-08T02:42:48.000Z","published_at":"2012-12-24T13:01:16.000Z","restored_at":null,"restored_by":null,"spam":false,"simulink":false,"admin_reviewed":false,"description_opc":"{\"relationships\":[{\"relationshipType\":\"http://schemas.mathworks.com/matlab/code/2013/relationships/document\",\"relationshipId\":\"rId1\",\"target\":\"/matlab/document.xml\"},{\"relationshipType\":\"http://schemas.mathworks.com/matlab/code/2013/relationships/output\",\"relationshipId\":\"rId2\",\"target\":\"/matlab/output.xml\"}],\"parts\":[{\"partUri\":\"/matlab/document.xml\",\"relationship\":[],\"contentType\":\"application/vnd.mathworks.matlab.code.document+xml\",\"content\":\"\u003c?xml version=\\\"1.0\\\" encoding=\\\"UTF-8\\\"?\u003e\u003cw:document xmlns:w=\\\"http://schemas.openxmlformats.org/wordprocessingml/2006/main\\\"\u003e\u003cw:body\u003e\u003cw:p\u003e\u003cw:pPr\u003e\u003cw:pStyle w:val=\\\"text\\\"/\u003e\u003c/w:pPr\u003e\u003cw:r\u003e\u003cw:t\u003eFor a given vector, say [6 3 8 2], return the ranks (ascending) of observations, i.e. [3 2 4 1]. Do not worry about tied ranks. If ties exist, what comes first takes the lower rank, e.g., [1 1 3] returns [1 2 3]. More exact treatment of ties will follow. No toolbox functions please!\u003c/w:t\u003e\u003c/w:r\u003e\u003c/w:p\u003e\u003c/w:body\u003e\u003c/w:document\u003e\"},{\"partUri\":\"/matlab/output.xml\",\"contentType\":\"text/xml\",\"content\":\"\u003c?xml version=\\\"1.0\\\" encoding=\\\"UTF-8\\\" standalone=\\\"no\\\" ?\u003e\u003cembeddedOutputs\u003e\u003cmetaData\u003e\u003cevaluationState\u003emanual\u003c/evaluationState\u003e\u003clayoutState\u003ecode\u003c/layoutState\u003e\u003coutputStatus\u003eready\u003c/outputStatus\u003e\u003c/metaData\u003e\u003coutputArray type=\\\"array\\\"/\u003e\u003cregionArray type=\\\"array\\\"/\u003e\u003c/embeddedOutputs\u003e\"}]}"},{"id":42762,"title":"Is 3D point set Co-Planar?","description":"This Challenge is to determine if four 3D integer points are co-planar.\r\nGiven a 4x3 matrix representing four x,y,z integer points, output True if the set is co-planar and False otherwise.\r\n\r\nExamples\r\n\r\n m = [0 0 0;1 0 0;0 1 0;0 0 1] \r\n Output: False, this point set is non-coplanar.\r\n\r\n m = [0 0 0;0 0 1;1 1 0;1 1 1]\r\n Output: True, this point set is co-planar.\r\n\r\nReference: The \u003chttp://68.173.157.131/Contest/Tetrahedra March 2016 Al Zimmermann Non-Coplanar contest\u003e is to maximize the number of points in an NxNxN cube with no 4 points in a common plane. Future challenge will be to find N=2 and N=3 solutions.\r\n\r\nTheory: Plane is defined as Ax+By+cZ=D. [A,B,C] can be found using cross of 3 points. D can be found by substitution using any of these 3 points. Co-Planarity of the fourth point is True if Ax4+By4+Cz4==D\r\n","description_html":"\u003cp\u003eThis Challenge is to determine if four 3D integer points are co-planar.\r\nGiven a 4x3 matrix representing four x,y,z integer points, output True if the set is co-planar and False otherwise.\u003c/p\u003e\u003cp\u003eExamples\u003c/p\u003e\u003cpre\u003e m = [0 0 0;1 0 0;0 1 0;0 0 1] \r\n Output: False, this point set is non-coplanar.\u003c/pre\u003e\u003cpre\u003e m = [0 0 0;0 0 1;1 1 0;1 1 1]\r\n Output: True, this point set is co-planar.\u003c/pre\u003e\u003cp\u003eReference: The \u003ca href = \"http://68.173.157.131/Contest/Tetrahedra\"\u003eMarch 2016 Al Zimmermann Non-Coplanar contest\u003c/a\u003e is to maximize the number of points in an NxNxN cube with no 4 points in a common plane. Future challenge will be to find N=2 and N=3 solutions.\u003c/p\u003e\u003cp\u003eTheory: Plane is defined as Ax+By+cZ=D. [A,B,C] can be found using cross of 3 points. D can be found by substitution using any of these 3 points. Co-Planarity of the fourth point is True if Ax4+By4+Cz4==D\u003c/p\u003e","function_template":"function TF = iscoplanar(m)\r\n% m is a 4x3 matrix\r\n  TF=false;\r\nend","test_suite":"%%\r\nm=[0 0 1;1 1 0;1 0 1;2 0 0];\r\ny_correct = false;\r\nassert(isequal(iscoplanar(m),y_correct))\r\n%%\r\nm=[0 0 1;1 1 0;1 0 1;2 1 2];\r\ny_correct = false;\r\nassert(isequal(iscoplanar(m),y_correct))\r\n%%\r\nm=[0 0 1;1 1 0;1 0 1;0 1 0];\r\ny_correct = true;\r\nassert(isequal(iscoplanar(m),y_correct))\r\n%%\r\nm=[0 0 1;1 1 0;1 0 1;2 1 0];\r\ny_correct = true;\r\nassert(isequal(iscoplanar(m),y_correct))\r\n%%\r\nm=[0 0 1;1 1 0;1 0 1;2 0 1];\r\ny_correct = true;\r\nassert(isequal(iscoplanar(m),y_correct))\r\n%%\r\nm=[2 0 0;1 2 0;2 1 1;2 2 2];\r\ny_correct = true;\r\nassert(isequal(iscoplanar(m),y_correct))\r\n%%\r\nm=[2 0 0;1 2 0;2 1 1;2 1 2];\r\ny_correct = false;\r\nassert(isequal(iscoplanar(m),y_correct))\r\n%%\r\nm=[0 0 0;1 0 0;0 1 0;0 0 1];\r\ny_correct = false;\r\nassert(isequal(iscoplanar(m),y_correct))\r\n%%\r\nm=[0 0 0;1 0 0;0 1 0;1 1 1];\r\ny_correct = false;\r\nassert(isequal(iscoplanar(m),y_correct))\r\n%%\r\nm=[0 0 0;1 0 0;0 1 0;1 1 0];\r\ny_correct = true;\r\nassert(isequal(iscoplanar(m),y_correct))\r\n%%\r\nm=[0 0 0;0 0 1;1 1 1;1 1 0];\r\ny_correct = true;\r\nassert(isequal(iscoplanar(m),y_correct))\r\n\r\n%0 0 0 \r\n%1 0 0 \r\n%0 1 0 \r\n%0 0 1 \r\n%1 1 1","published":true,"deleted":false,"likes_count":1,"comments_count":0,"created_by":3097,"edited_by":null,"edited_at":null,"deleted_by":null,"deleted_at":null,"solvers_count":26,"test_suite_updated_at":null,"rescore_all_solutions":false,"group_id":1,"created_at":"2016-03-05T21:58:07.000Z","updated_at":"2026-04-04T03:46:57.000Z","published_at":"2016-03-06T19:31:31.000Z","restored_at":null,"restored_by":null,"spam":false,"simulink":false,"admin_reviewed":false,"description_opc":"{\"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\":\"\u003c?xml version=\\\"1.0\\\" encoding=\\\"UTF-8\\\"?\u003e\\n\u003cw:document xmlns:w=\\\"http://schemas.openxmlformats.org/wordprocessingml/2006/main\\\"\u003e\u003cw:body\u003e\u003cw:p\u003e\u003cw:pPr\u003e\u003cw:pStyle w:val=\\\"text\\\"/\u003e\u003c/w:pPr\u003e\u003cw:r\u003e\u003cw:t\u003eThis Challenge is to determine if four 3D integer points are co-planar. Given a 4x3 matrix representing four x,y,z integer points, output True if the set is co-planar and False otherwise.\u003c/w:t\u003e\u003c/w:r\u003e\u003c/w:p\u003e\u003cw:p\u003e\u003cw:pPr\u003e\u003cw:pStyle w:val=\\\"text\\\"/\u003e\u003c/w:pPr\u003e\u003cw:r\u003e\u003cw:t\u003eExamples\u003c/w:t\u003e\u003c/w:r\u003e\u003c/w:p\u003e\u003cw:p\u003e\u003cw:pPr\u003e\u003cw:pStyle w:val=\\\"code\\\"/\u003e\u003c/w:pPr\u003e\u003cw:r\u003e\u003cw:t\u003e\u003c![CDATA[ m = [0 0 0;1 0 0;0 1 0;0 0 1] \\n Output: False, this point set is non-coplanar.\\n\\n m = [0 0 0;0 0 1;1 1 0;1 1 1]\\n Output: True, this point set is co-planar.]]\u003e\u003c/w:t\u003e\u003c/w:r\u003e\u003c/w:p\u003e\u003cw:p\u003e\u003cw:pPr\u003e\u003cw:pStyle w:val=\\\"text\\\"/\u003e\u003c/w:pPr\u003e\u003cw:r\u003e\u003cw:t\u003eReference: The\u003c/w:t\u003e\u003c/w:r\u003e\u003cw:r\u003e\u003cw:t\u003e \u003c/w:t\u003e\u003c/w:r\u003e\u003cw:hyperlink w:docLocation=\\\"http://68.173.157.131/Contest/Tetrahedra\\\"\u003e\u003cw:r\u003e\u003cw:t\u003eMarch 2016 Al Zimmermann Non-Coplanar contest\u003c/w:t\u003e\u003c/w:r\u003e\u003c/w:hyperlink\u003e\u003cw:r\u003e\u003cw:t\u003e is to maximize the number of points in an NxNxN cube with no 4 points in a common plane. Future challenge will be to find N=2 and N=3 solutions.\u003c/w:t\u003e\u003c/w:r\u003e\u003c/w:p\u003e\u003cw:p\u003e\u003cw:pPr\u003e\u003cw:pStyle w:val=\\\"text\\\"/\u003e\u003c/w:pPr\u003e\u003cw:r\u003e\u003cw:t\u003eTheory: Plane is defined as Ax+By+cZ=D. [A,B,C] can be found using cross of 3 points. D can be found by substitution using any of these 3 points. Co-Planarity of the fourth point is True if Ax4+By4+Cz4==D\u003c/w:t\u003e\u003c/w:r\u003e\u003c/w:p\u003e\u003c/w:body\u003e\u003c/w:document\u003e\"},{\"partUri\":\"/matlab/output.xml\",\"contentType\":\"text/xml\",\"content\":\"\u003c?xml version=\\\"1.0\\\" encoding=\\\"UTF-8\\\" standalone=\\\"no\\\" ?\u003e\u003cembeddedOutputs\u003e\u003cmetaData\u003e\u003cevaluationState\u003emanual\u003c/evaluationState\u003e\u003clayoutState\u003ecode\u003c/layoutState\u003e\u003coutputStatus\u003eready\u003c/outputStatus\u003e\u003c/metaData\u003e\u003coutputArray type=\\\"array\\\"/\u003e\u003cregionArray type=\\\"array\\\"/\u003e\u003c/embeddedOutputs\u003e\"}]}"},{"id":1088,"title":"Rank of magic square (for beginners)","description":"Compute the rank r of a magic square of order n WITHOUT rank and magic functions.","description_html":"\u003cp\u003eCompute the rank r of a magic square of order n WITHOUT rank and magic functions.\u003c/p\u003e","function_template":"function r = mag_rang(n)\r\n  r = n;\r\nend","test_suite":"%%\r\nn = 20;\r\nr = 3;\r\nfiletext = fileread('mag_rang.m');\r\nassert(isequal(mag_rang(n),r))\r\nassert(isempty(strfind(filetext, 'rank')))\r\nassert(isempty(strfind(filetext, 'magic')))\r\n%%\r\nn = 4;\r\nr = 3;\r\nfiletext = fileread('mag_rang.m');\r\nassert(isequal(mag_rang(n),r))\r\nassert(isempty(strfind(filetext, 'rank')))\r\nassert(isempty(strfind(filetext, 'magic')))\r\n%%\r\nn = 15;\r\nr = 15;\r\nfiletext = fileread('mag_rang.m');\r\nassert(isequal(mag_rang(n),r))\r\nassert(isempty(strfind(filetext, 'rank')))\r\nassert(isempty(strfind(filetext, 'magic')))\r\n%%\r\nn = 18;\r\nr = 11;\r\nfiletext = fileread('mag_rang.m');\r\nassert(isequal(mag_rang(n),r))\r\nassert(isempty(strfind(filetext, 'rank')))\r\nassert(isempty(strfind(filetext, 'magic')))\r\n%%\r\nn = 16;\r\nr = 3;\r\nfiletext = fileread('mag_rang.m');\r\nassert(isequal(mag_rang(n),r))\r\nassert(isempty(strfind(filetext, 'rank')))\r\nassert(isempty(strfind(filetext, 'magic')))\r\n%%\r\nn = 170;\r\nr = 87;\r\nfiletext = fileread('mag_rang.m');\r\nassert(isequal(mag_rang(n),r))\r\nassert(isempty(strfind(filetext, 'rank')))\r\nassert(isempty(strfind(filetext, 'magic')))\r\n%%\r\nn = 112;\r\nr = 3;\r\nfiletext = fileread('mag_rang.m');\r\nassert(isequal(mag_rang(n),r))\r\nassert(isempty(strfind(filetext, 'rank')))\r\nassert(isempty(strfind(filetext, 'magic')))\r\n%%\r\nn = 170;\r\nr = 87;\r\nfiletext = fileread('mag_rang.m');\r\nassert(isequal(mag_rang(n),r))\r\nassert(isempty(strfind(filetext, 'rank')))\r\nassert(isempty(strfind(filetext, 'magic')))","published":true,"deleted":false,"likes_count":1,"comments_count":6,"created_by":5390,"edited_by":null,"edited_at":null,"deleted_by":null,"deleted_at":null,"solvers_count":46,"test_suite_updated_at":null,"rescore_all_solutions":false,"group_id":1,"created_at":"2012-12-04T01:21:22.000Z","updated_at":"2025-12-02T16:10:10.000Z","published_at":"2012-12-04T01:36:44.000Z","restored_at":null,"restored_by":null,"spam":false,"simulink":false,"admin_reviewed":false,"description_opc":"{\"relationships\":[{\"relationshipType\":\"http://schemas.mathworks.com/matlab/code/2013/relationships/document\",\"relationshipId\":\"rId1\",\"target\":\"/matlab/document.xml\"},{\"relationshipType\":\"http://schemas.mathworks.com/matlab/code/2013/relationships/output\",\"relationshipId\":\"rId2\",\"target\":\"/matlab/output.xml\"}],\"parts\":[{\"partUri\":\"/matlab/document.xml\",\"relationship\":[],\"contentType\":\"application/vnd.mathworks.matlab.code.document+xml\",\"content\":\"\u003c?xml version=\\\"1.0\\\" encoding=\\\"UTF-8\\\"?\u003e\u003cw:document xmlns:w=\\\"http://schemas.openxmlformats.org/wordprocessingml/2006/main\\\"\u003e\u003cw:body\u003e\u003cw:p\u003e\u003cw:pPr\u003e\u003cw:pStyle w:val=\\\"text\\\"/\u003e\u003c/w:pPr\u003e\u003cw:r\u003e\u003cw:t\u003eCompute the rank r of a magic square of order n WITHOUT rank and magic functions.\u003c/w:t\u003e\u003c/w:r\u003e\u003c/w:p\u003e\u003c/w:body\u003e\u003c/w:document\u003e\"},{\"partUri\":\"/matlab/output.xml\",\"contentType\":\"text/xml\",\"content\":\"\u003c?xml version=\\\"1.0\\\" encoding=\\\"UTF-8\\\" standalone=\\\"no\\\" ?\u003e\u003cembeddedOutputs\u003e\u003cmetaData\u003e\u003cevaluationState\u003emanual\u003c/evaluationState\u003e\u003clayoutState\u003ecode\u003c/layoutState\u003e\u003coutputStatus\u003eready\u003c/outputStatus\u003e\u003c/metaData\u003e\u003coutputArray type=\\\"array\\\"/\u003e\u003cregionArray type=\\\"array\\\"/\u003e\u003c/embeddedOutputs\u003e\"}]}"}],"problem_search":{"errors":[],"problems":[{"id":47508,"title":"Convert sorting indices to ranks","description":null,"description_html":"\u003cdiv style = \"text-align: start; line-height: 20.44px; min-height: 0px; white-space: normal; color: rgb(0, 0, 0); font-family: Menlo, Monaco, Consolas, monospace; font-style: normal; font-size: 14px; font-weight: 400; text-decoration: none solid rgb(0, 0, 0); white-space: normal; \"\u003e\u003cdiv style=\"block-size: 93px; display: block; min-width: 0px; padding-block-start: 0px; padding-top: 0px; perspective-origin: 407px 46.5px; transform-origin: 407px 46.5px; vertical-align: baseline; \"\u003e\u003cdiv style=\"block-size: 63px; font-family: Helvetica, Arial, sans-serif; line-height: 21px; margin-block-end: 9px; margin-block-start: 2px; margin-bottom: 9px; margin-inline-end: 10px; margin-inline-start: 4px; margin-left: 4px; margin-right: 10px; margin-top: 2px; perspective-origin: 384px 31.5px; text-align: left; transform-origin: 384px 31.5px; white-space: pre-wrap; margin-left: 4px; margin-top: 2px; margin-bottom: 9px; margin-right: 10px; \"\u003e\u003cspan style=\"block-size: auto; display: inline; margin-block-end: 0px; margin-block-start: 0px; margin-bottom: 0px; margin-inline-end: 0px; margin-inline-start: 0px; margin-left: 0px; margin-right: 0px; margin-top: 0px; perspective-origin: 0px 0px; transform-origin: 0px 0px; \"\u003e\u003cspan style=\"\"\u003eThe second output of sort() is the sorting index vector, telling where the corresponding element in the sorted vector was in the raw vector. However sometimes we want to know where the elements of the raw vector goes into the sorted vector, i.e., ranks.\u003c/span\u003e\u003c/span\u003e\u003c/div\u003e\u003cdiv style=\"block-size: 21px; font-family: Helvetica, Arial, sans-serif; line-height: 21px; margin-block-end: 9px; margin-block-start: 2px; margin-bottom: 9px; margin-inline-end: 10px; margin-inline-start: 4px; margin-left: 4px; margin-right: 10px; margin-top: 2px; perspective-origin: 384px 10.5px; text-align: left; transform-origin: 384px 10.5px; white-space: pre-wrap; margin-left: 4px; margin-top: 2px; margin-bottom: 9px; margin-right: 10px; \"\u003e\u003cspan style=\"block-size: auto; display: inline; margin-block-end: 0px; margin-block-start: 0px; margin-bottom: 0px; margin-inline-end: 0px; margin-inline-start: 0px; margin-left: 0px; margin-right: 0px; margin-top: 0px; perspective-origin: 0px 0px; transform-origin: 0px 0px; \"\u003e\u003cspan style=\"\"\u003eCan you find the shortest solution?\u003c/span\u003e\u003c/span\u003e\u003c/div\u003e\u003c/div\u003e\u003c/div\u003e","function_template":"function Ranks = SortingIndices2Ranks(SortingIndices)\r\n  Ranks=SortingIndices;\r\nend","test_suite":"%%\r\nRawVector=rand(10,1);\r\n[SortedVector,SortingIndices]=sort(RawVector);\r\nRanks=SortingIndices2Ranks(SortingIndices);\r\nassert(isequal(SortedVector(Ranks),RawVector));","published":true,"deleted":false,"likes_count":1,"comments_count":0,"created_by":362068,"edited_by":null,"edited_at":null,"deleted_by":null,"deleted_at":null,"solvers_count":13,"test_suite_updated_at":null,"rescore_all_solutions":false,"group_id":1,"created_at":"2020-11-15T04:05:17.000Z","updated_at":"2025-11-28T17:59:25.000Z","published_at":"2020-11-15T04:05:17.000Z","restored_at":null,"restored_by":null,"spam":false,"simulink":false,"admin_reviewed":false,"description_opc":"{\"parts\":[{\"partUri\":\"/matlab/document.xml\",\"contentType\":\"application/vnd.mathworks.matlab.code.document+xml\",\"content\":\"\u003c?xml version=\\\"1.0\\\" encoding=\\\"UTF-8\\\"?\u003e\u003cw:document xmlns:w=\\\"http://schemas.openxmlformats.org/wordprocessingml/2006/main\\\"\u003e\u003cw:body\u003e\u003cw:p\u003e\u003cw:pPr\u003e\u003cw:pStyle w:val=\\\"text\\\"/\u003e\u003cw:jc w:val=\\\"left\\\"/\u003e\u003c/w:pPr\u003e\u003cw:r\u003e\u003cw:t\u003eThe second output of sort() is the sorting index vector, telling where the corresponding element in the sorted vector was in the raw vector. However sometimes we want to know where the elements of the raw vector goes into the sorted vector, i.e., ranks.\u003c/w:t\u003e\u003c/w:r\u003e\u003c/w:p\u003e\u003cw:p\u003e\u003cw:pPr\u003e\u003cw:pStyle w:val=\\\"text\\\"/\u003e\u003cw:jc w:val=\\\"left\\\"/\u003e\u003c/w:pPr\u003e\u003cw:r\u003e\u003cw:t\u003eCan you find the shortest solution?\u003c/w:t\u003e\u003c/w:r\u003e\u003c/w:p\u003e\u003c/w:body\u003e\u003c/w:document\u003e\",\"relationship\":null}],\"relationships\":[{\"relationshipType\":\"http://schemas.mathworks.com/matlab/code/2013/relationships/document\",\"target\":\"/matlab/document.xml\",\"relationshipId\":\"rId1\"}]}"},{"id":1134,"title":"Get ranks of values in a vector","description":"For a given vector, say [6 3 8 2], return the ranks (ascending) of observations, i.e. [3 2 4 1]. Do not worry about tied ranks. If ties exist, what comes first takes the lower rank, e.g., [1 1 3] returns [1 2 3]. More exact treatment of ties will follow. No toolbox functions please!","description_html":"\u003cp\u003eFor a given vector, say [6 3 8 2], return the ranks (ascending) of observations, i.e. [3 2 4 1]. Do not worry about tied ranks. If ties exist, what comes first takes the lower rank, e.g., [1 1 3] returns [1 2 3]. More exact treatment of ties will follow. No toolbox functions please!\u003c/p\u003e","function_template":"function y = getrank(x)\r\n  y = x;\r\nend","test_suite":"%%\r\nx = 0:9;\r\ny_correct = 1:10;\r\nassert(isequal(getrank(x),y_correct))\r\n%%\r\nx = 9:-1:0;\r\ny_correct = 10:-1:1;\r\nassert(isequal(getrank(x),y_correct))\r\n%%\r\nx = [.5 .8 .1 .9 .7];\r\ny_correct = [2 4 1 5 3];\r\nassert(isequal(getrank(x),y_correct))\r\n%%\r\nx = [2 -1 7 -6 3 2];\r\ny_correct = [3 2 6 1 5 4] ;\r\nassert(isequal(getrank(x),y_correct))","published":true,"deleted":false,"likes_count":2,"comments_count":0,"created_by":3399,"edited_by":null,"edited_at":null,"deleted_by":null,"deleted_at":null,"solvers_count":57,"test_suite_updated_at":null,"rescore_all_solutions":false,"group_id":1,"created_at":"2012-12-24T13:01:10.000Z","updated_at":"2025-12-08T02:42:48.000Z","published_at":"2012-12-24T13:01:16.000Z","restored_at":null,"restored_by":null,"spam":false,"simulink":false,"admin_reviewed":false,"description_opc":"{\"relationships\":[{\"relationshipType\":\"http://schemas.mathworks.com/matlab/code/2013/relationships/document\",\"relationshipId\":\"rId1\",\"target\":\"/matlab/document.xml\"},{\"relationshipType\":\"http://schemas.mathworks.com/matlab/code/2013/relationships/output\",\"relationshipId\":\"rId2\",\"target\":\"/matlab/output.xml\"}],\"parts\":[{\"partUri\":\"/matlab/document.xml\",\"relationship\":[],\"contentType\":\"application/vnd.mathworks.matlab.code.document+xml\",\"content\":\"\u003c?xml version=\\\"1.0\\\" encoding=\\\"UTF-8\\\"?\u003e\u003cw:document xmlns:w=\\\"http://schemas.openxmlformats.org/wordprocessingml/2006/main\\\"\u003e\u003cw:body\u003e\u003cw:p\u003e\u003cw:pPr\u003e\u003cw:pStyle w:val=\\\"text\\\"/\u003e\u003c/w:pPr\u003e\u003cw:r\u003e\u003cw:t\u003eFor a given vector, say [6 3 8 2], return the ranks (ascending) of observations, i.e. [3 2 4 1]. Do not worry about tied ranks. If ties exist, what comes first takes the lower rank, e.g., [1 1 3] returns [1 2 3]. More exact treatment of ties will follow. No toolbox functions please!\u003c/w:t\u003e\u003c/w:r\u003e\u003c/w:p\u003e\u003c/w:body\u003e\u003c/w:document\u003e\"},{\"partUri\":\"/matlab/output.xml\",\"contentType\":\"text/xml\",\"content\":\"\u003c?xml version=\\\"1.0\\\" encoding=\\\"UTF-8\\\" standalone=\\\"no\\\" ?\u003e\u003cembeddedOutputs\u003e\u003cmetaData\u003e\u003cevaluationState\u003emanual\u003c/evaluationState\u003e\u003clayoutState\u003ecode\u003c/layoutState\u003e\u003coutputStatus\u003eready\u003c/outputStatus\u003e\u003c/metaData\u003e\u003coutputArray type=\\\"array\\\"/\u003e\u003cregionArray type=\\\"array\\\"/\u003e\u003c/embeddedOutputs\u003e\"}]}"},{"id":42762,"title":"Is 3D point set Co-Planar?","description":"This Challenge is to determine if four 3D integer points are co-planar.\r\nGiven a 4x3 matrix representing four x,y,z integer points, output True if the set is co-planar and False otherwise.\r\n\r\nExamples\r\n\r\n m = [0 0 0;1 0 0;0 1 0;0 0 1] \r\n Output: False, this point set is non-coplanar.\r\n\r\n m = [0 0 0;0 0 1;1 1 0;1 1 1]\r\n Output: True, this point set is co-planar.\r\n\r\nReference: The \u003chttp://68.173.157.131/Contest/Tetrahedra March 2016 Al Zimmermann Non-Coplanar contest\u003e is to maximize the number of points in an NxNxN cube with no 4 points in a common plane. Future challenge will be to find N=2 and N=3 solutions.\r\n\r\nTheory: Plane is defined as Ax+By+cZ=D. [A,B,C] can be found using cross of 3 points. D can be found by substitution using any of these 3 points. Co-Planarity of the fourth point is True if Ax4+By4+Cz4==D\r\n","description_html":"\u003cp\u003eThis Challenge is to determine if four 3D integer points are co-planar.\r\nGiven a 4x3 matrix representing four x,y,z integer points, output True if the set is co-planar and False otherwise.\u003c/p\u003e\u003cp\u003eExamples\u003c/p\u003e\u003cpre\u003e m = [0 0 0;1 0 0;0 1 0;0 0 1] \r\n Output: False, this point set is non-coplanar.\u003c/pre\u003e\u003cpre\u003e m = [0 0 0;0 0 1;1 1 0;1 1 1]\r\n Output: True, this point set is co-planar.\u003c/pre\u003e\u003cp\u003eReference: The \u003ca href = \"http://68.173.157.131/Contest/Tetrahedra\"\u003eMarch 2016 Al Zimmermann Non-Coplanar contest\u003c/a\u003e is to maximize the number of points in an NxNxN cube with no 4 points in a common plane. Future challenge will be to find N=2 and N=3 solutions.\u003c/p\u003e\u003cp\u003eTheory: Plane is defined as Ax+By+cZ=D. [A,B,C] can be found using cross of 3 points. D can be found by substitution using any of these 3 points. Co-Planarity of the fourth point is True if Ax4+By4+Cz4==D\u003c/p\u003e","function_template":"function TF = iscoplanar(m)\r\n% m is a 4x3 matrix\r\n  TF=false;\r\nend","test_suite":"%%\r\nm=[0 0 1;1 1 0;1 0 1;2 0 0];\r\ny_correct = false;\r\nassert(isequal(iscoplanar(m),y_correct))\r\n%%\r\nm=[0 0 1;1 1 0;1 0 1;2 1 2];\r\ny_correct = false;\r\nassert(isequal(iscoplanar(m),y_correct))\r\n%%\r\nm=[0 0 1;1 1 0;1 0 1;0 1 0];\r\ny_correct = true;\r\nassert(isequal(iscoplanar(m),y_correct))\r\n%%\r\nm=[0 0 1;1 1 0;1 0 1;2 1 0];\r\ny_correct = true;\r\nassert(isequal(iscoplanar(m),y_correct))\r\n%%\r\nm=[0 0 1;1 1 0;1 0 1;2 0 1];\r\ny_correct = true;\r\nassert(isequal(iscoplanar(m),y_correct))\r\n%%\r\nm=[2 0 0;1 2 0;2 1 1;2 2 2];\r\ny_correct = true;\r\nassert(isequal(iscoplanar(m),y_correct))\r\n%%\r\nm=[2 0 0;1 2 0;2 1 1;2 1 2];\r\ny_correct = false;\r\nassert(isequal(iscoplanar(m),y_correct))\r\n%%\r\nm=[0 0 0;1 0 0;0 1 0;0 0 1];\r\ny_correct = false;\r\nassert(isequal(iscoplanar(m),y_correct))\r\n%%\r\nm=[0 0 0;1 0 0;0 1 0;1 1 1];\r\ny_correct = false;\r\nassert(isequal(iscoplanar(m),y_correct))\r\n%%\r\nm=[0 0 0;1 0 0;0 1 0;1 1 0];\r\ny_correct = true;\r\nassert(isequal(iscoplanar(m),y_correct))\r\n%%\r\nm=[0 0 0;0 0 1;1 1 1;1 1 0];\r\ny_correct = true;\r\nassert(isequal(iscoplanar(m),y_correct))\r\n\r\n%0 0 0 \r\n%1 0 0 \r\n%0 1 0 \r\n%0 0 1 \r\n%1 1 1","published":true,"deleted":false,"likes_count":1,"comments_count":0,"created_by":3097,"edited_by":null,"edited_at":null,"deleted_by":null,"deleted_at":null,"solvers_count":26,"test_suite_updated_at":null,"rescore_all_solutions":false,"group_id":1,"created_at":"2016-03-05T21:58:07.000Z","updated_at":"2026-04-04T03:46:57.000Z","published_at":"2016-03-06T19:31:31.000Z","restored_at":null,"restored_by":null,"spam":false,"simulink":false,"admin_reviewed":false,"description_opc":"{\"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\":\"\u003c?xml version=\\\"1.0\\\" encoding=\\\"UTF-8\\\"?\u003e\\n\u003cw:document xmlns:w=\\\"http://schemas.openxmlformats.org/wordprocessingml/2006/main\\\"\u003e\u003cw:body\u003e\u003cw:p\u003e\u003cw:pPr\u003e\u003cw:pStyle w:val=\\\"text\\\"/\u003e\u003c/w:pPr\u003e\u003cw:r\u003e\u003cw:t\u003eThis Challenge is to determine if four 3D integer points are co-planar. Given a 4x3 matrix representing four x,y,z integer points, output True if the set is co-planar and False otherwise.\u003c/w:t\u003e\u003c/w:r\u003e\u003c/w:p\u003e\u003cw:p\u003e\u003cw:pPr\u003e\u003cw:pStyle w:val=\\\"text\\\"/\u003e\u003c/w:pPr\u003e\u003cw:r\u003e\u003cw:t\u003eExamples\u003c/w:t\u003e\u003c/w:r\u003e\u003c/w:p\u003e\u003cw:p\u003e\u003cw:pPr\u003e\u003cw:pStyle w:val=\\\"code\\\"/\u003e\u003c/w:pPr\u003e\u003cw:r\u003e\u003cw:t\u003e\u003c![CDATA[ m = [0 0 0;1 0 0;0 1 0;0 0 1] \\n Output: False, this point set is non-coplanar.\\n\\n m = [0 0 0;0 0 1;1 1 0;1 1 1]\\n Output: True, this point set is co-planar.]]\u003e\u003c/w:t\u003e\u003c/w:r\u003e\u003c/w:p\u003e\u003cw:p\u003e\u003cw:pPr\u003e\u003cw:pStyle w:val=\\\"text\\\"/\u003e\u003c/w:pPr\u003e\u003cw:r\u003e\u003cw:t\u003eReference: The\u003c/w:t\u003e\u003c/w:r\u003e\u003cw:r\u003e\u003cw:t\u003e \u003c/w:t\u003e\u003c/w:r\u003e\u003cw:hyperlink w:docLocation=\\\"http://68.173.157.131/Contest/Tetrahedra\\\"\u003e\u003cw:r\u003e\u003cw:t\u003eMarch 2016 Al Zimmermann Non-Coplanar contest\u003c/w:t\u003e\u003c/w:r\u003e\u003c/w:hyperlink\u003e\u003cw:r\u003e\u003cw:t\u003e is to maximize the number of points in an NxNxN cube with no 4 points in a common plane. Future challenge will be to find N=2 and N=3 solutions.\u003c/w:t\u003e\u003c/w:r\u003e\u003c/w:p\u003e\u003cw:p\u003e\u003cw:pPr\u003e\u003cw:pStyle w:val=\\\"text\\\"/\u003e\u003c/w:pPr\u003e\u003cw:r\u003e\u003cw:t\u003eTheory: Plane is defined as Ax+By+cZ=D. [A,B,C] can be found using cross of 3 points. D can be found by substitution using any of these 3 points. Co-Planarity of the fourth point is True if Ax4+By4+Cz4==D\u003c/w:t\u003e\u003c/w:r\u003e\u003c/w:p\u003e\u003c/w:body\u003e\u003c/w:document\u003e\"},{\"partUri\":\"/matlab/output.xml\",\"contentType\":\"text/xml\",\"content\":\"\u003c?xml version=\\\"1.0\\\" encoding=\\\"UTF-8\\\" standalone=\\\"no\\\" ?\u003e\u003cembeddedOutputs\u003e\u003cmetaData\u003e\u003cevaluationState\u003emanual\u003c/evaluationState\u003e\u003clayoutState\u003ecode\u003c/layoutState\u003e\u003coutputStatus\u003eready\u003c/outputStatus\u003e\u003c/metaData\u003e\u003coutputArray type=\\\"array\\\"/\u003e\u003cregionArray type=\\\"array\\\"/\u003e\u003c/embeddedOutputs\u003e\"}]}"},{"id":1088,"title":"Rank of magic square (for beginners)","description":"Compute the rank r of a magic square of order n WITHOUT rank and magic functions.","description_html":"\u003cp\u003eCompute the rank r of a magic square of order n WITHOUT rank and magic functions.\u003c/p\u003e","function_template":"function r = mag_rang(n)\r\n  r = n;\r\nend","test_suite":"%%\r\nn = 20;\r\nr = 3;\r\nfiletext = fileread('mag_rang.m');\r\nassert(isequal(mag_rang(n),r))\r\nassert(isempty(strfind(filetext, 'rank')))\r\nassert(isempty(strfind(filetext, 'magic')))\r\n%%\r\nn = 4;\r\nr = 3;\r\nfiletext = fileread('mag_rang.m');\r\nassert(isequal(mag_rang(n),r))\r\nassert(isempty(strfind(filetext, 'rank')))\r\nassert(isempty(strfind(filetext, 'magic')))\r\n%%\r\nn = 15;\r\nr = 15;\r\nfiletext = fileread('mag_rang.m');\r\nassert(isequal(mag_rang(n),r))\r\nassert(isempty(strfind(filetext, 'rank')))\r\nassert(isempty(strfind(filetext, 'magic')))\r\n%%\r\nn = 18;\r\nr = 11;\r\nfiletext = fileread('mag_rang.m');\r\nassert(isequal(mag_rang(n),r))\r\nassert(isempty(strfind(filetext, 'rank')))\r\nassert(isempty(strfind(filetext, 'magic')))\r\n%%\r\nn = 16;\r\nr = 3;\r\nfiletext = fileread('mag_rang.m');\r\nassert(isequal(mag_rang(n),r))\r\nassert(isempty(strfind(filetext, 'rank')))\r\nassert(isempty(strfind(filetext, 'magic')))\r\n%%\r\nn = 170;\r\nr = 87;\r\nfiletext = fileread('mag_rang.m');\r\nassert(isequal(mag_rang(n),r))\r\nassert(isempty(strfind(filetext, 'rank')))\r\nassert(isempty(strfind(filetext, 'magic')))\r\n%%\r\nn = 112;\r\nr = 3;\r\nfiletext = fileread('mag_rang.m');\r\nassert(isequal(mag_rang(n),r))\r\nassert(isempty(strfind(filetext, 'rank')))\r\nassert(isempty(strfind(filetext, 'magic')))\r\n%%\r\nn = 170;\r\nr = 87;\r\nfiletext = fileread('mag_rang.m');\r\nassert(isequal(mag_rang(n),r))\r\nassert(isempty(strfind(filetext, 'rank')))\r\nassert(isempty(strfind(filetext, 'magic')))","published":true,"deleted":false,"likes_count":1,"comments_count":6,"created_by":5390,"edited_by":null,"edited_at":null,"deleted_by":null,"deleted_at":null,"solvers_count":46,"test_suite_updated_at":null,"rescore_all_solutions":false,"group_id":1,"created_at":"2012-12-04T01:21:22.000Z","updated_at":"2025-12-02T16:10:10.000Z","published_at":"2012-12-04T01:36:44.000Z","restored_at":null,"restored_by":null,"spam":false,"simulink":false,"admin_reviewed":false,"description_opc":"{\"relationships\":[{\"relationshipType\":\"http://schemas.mathworks.com/matlab/code/2013/relationships/document\",\"relationshipId\":\"rId1\",\"target\":\"/matlab/document.xml\"},{\"relationshipType\":\"http://schemas.mathworks.com/matlab/code/2013/relationships/output\",\"relationshipId\":\"rId2\",\"target\":\"/matlab/output.xml\"}],\"parts\":[{\"partUri\":\"/matlab/document.xml\",\"relationship\":[],\"contentType\":\"application/vnd.mathworks.matlab.code.document+xml\",\"content\":\"\u003c?xml version=\\\"1.0\\\" encoding=\\\"UTF-8\\\"?\u003e\u003cw:document xmlns:w=\\\"http://schemas.openxmlformats.org/wordprocessingml/2006/main\\\"\u003e\u003cw:body\u003e\u003cw:p\u003e\u003cw:pPr\u003e\u003cw:pStyle w:val=\\\"text\\\"/\u003e\u003c/w:pPr\u003e\u003cw:r\u003e\u003cw:t\u003eCompute the rank r of a magic square of order n WITHOUT rank and magic functions.\u003c/w:t\u003e\u003c/w:r\u003e\u003c/w:p\u003e\u003c/w:body\u003e\u003c/w:document\u003e\"},{\"partUri\":\"/matlab/output.xml\",\"contentType\":\"text/xml\",\"content\":\"\u003c?xml version=\\\"1.0\\\" encoding=\\\"UTF-8\\\" standalone=\\\"no\\\" ?\u003e\u003cembeddedOutputs\u003e\u003cmetaData\u003e\u003cevaluationState\u003emanual\u003c/evaluationState\u003e\u003clayoutState\u003ecode\u003c/layoutState\u003e\u003coutputStatus\u003eready\u003c/outputStatus\u003e\u003c/metaData\u003e\u003coutputArray type=\\\"array\\\"/\u003e\u003cregionArray type=\\\"array\\\"/\u003e\u003c/embeddedOutputs\u003e\"}]}"}],"term":"tag:\"rank\"","current_player_id":null,"fields":[{"name":"page","type":"integer","callback":null,"default":1,"directive":null,"facet":null,"facet_method":"and","operator":null,"param":null,"static":null,"prepend":true},{"name":"per_page","type":"integer","callback":null,"default":50,"directive":null,"facet":null,"facet_method":"and","operator":null,"param":null,"static":null,"prepend":true},{"name":"sort","type":"string","callback":null,"default":null,"directive":null,"facet":null,"facet_method":"and","operator":null,"param":null,"static":null,"prepend":true},{"name":"body","type":"text","callback":null,"default":"*:*","directive":null,"facet":null,"facet_method":"and","operator":null,"param":"term","static":null,"prepend":false},{"name":"group","type":"string","callback":null,"default":null,"directive":"group","facet":true,"facet_method":"and","operator":null,"param":"term","static":null,"prepend":true},{"name":"difficulty_rating_bin","type":"string","callback":null,"default":null,"directive":"difficulty_rating_bin","facet":true,"facet_method":"and","operator":null,"param":"term","static":null,"prepend":true},{"name":"id","type":"integer","callback":null,"default":null,"directive":"id","facet":null,"facet_method":"and","operator":null,"param":"term","static":null,"prepend":true},{"name":"tag","type":"string","callback":null,"default":null,"directive":"tag","facet":null,"facet_method":"and","operator":null,"param":"term","static":null,"prepend":true},{"name":"product","type":"string","callback":null,"default":null,"directive":"product","facet":null,"facet_method":"and","operator":null,"param":"term","static":null,"prepend":true},{"name":"created_at","type":"timeframe","callback":{},"default":null,"directive":"created_at","facet":null,"facet_method":"and","operator":null,"param":"term","static":null,"prepend":true},{"name":"profile_id","type":"integer","callback":null,"default":null,"directive":"author_id","facet":null,"facet_method":"and","operator":null,"param":"term","static":null,"prepend":true},{"name":"created_by","type":"string","callback":null,"default":null,"directive":"author","facet":null,"facet_method":"and","operator":null,"param":"term","static":null,"prepend":true},{"name":"player_id","type":"integer","callback":null,"default":null,"directive":"solver_id","facet":null,"facet_method":"and","operator":null,"param":"term","static":null,"prepend":true},{"name":"player","type":"string","callback":null,"default":null,"directive":"solver","facet":null,"facet_method":"and","operator":null,"param":"term","static":null,"prepend":true},{"name":"solvers_count","type":"integer","callback":null,"default":null,"directive":"solvers_count","facet":null,"facet_method":"and","operator":null,"param":"term","static":null,"prepend":true},{"name":"comments_count","type":"integer","callback":null,"default":null,"directive":"comments_count","facet":null,"facet_method":"and","operator":null,"param":"term","static":null,"prepend":true},{"name":"likes_count","type":"integer","callback":null,"default":null,"directive":"likes_count","facet":null,"facet_method":"and","operator":null,"param":"term","static":null,"prepend":true},{"name":"leader_id","type":"integer","callback":null,"default":null,"directive":"leader_id","facet":null,"facet_method":"and","operator":null,"param":"term","static":null,"prepend":true},{"name":"leading_solution","type":"integer","callback":null,"default":null,"directive":"leading_solution","facet":null,"facet_method":"and","operator":null,"param":"term","static":null,"prepend":true}],"filters":[{"name":"asset_type","type":"string","callback":null,"default":null,"directive":null,"facet":null,"facet_method":"and","operator":null,"param":null,"static":"\"cody:problem\"","prepend":true},{"name":"profile_id","type":"integer","callback":{},"default":null,"directive":null,"facet":null,"facet_method":"and","operator":null,"param":"author_id","static":null,"prepend":true}],"query":{"params":{"per_page":50,"term":"tag:\"rank\"","current_player":null,"sort":"map(difficulty_value,0,0,999) asc"},"parser":"MathWorks::Search::Solr::QueryParser","directives":{"term":{"directives":{"tag":[["tag:\"rank\"","","\"","rank","\""]]}}},"facets":{"#\u003cMathWorks::Search::Field:0x00007ff7fda4b418\u003e":null,"#\u003cMathWorks::Search::Field:0x00007ff7fda4b378\u003e":null},"filters":{"#\u003cMathWorks::Search::Field:0x00007ff7fda4aab8\u003e":"\"cody:problem\""},"fields":{"#\u003cMathWorks::Search::Field:0x00007ff7fda4b698\u003e":1,"#\u003cMathWorks::Search::Field:0x00007ff7fda4b5f8\u003e":50,"#\u003cMathWorks::Search::Field:0x00007ff7fda4b558\u003e":"map(difficulty_value,0,0,999) asc","#\u003cMathWorks::Search::Field:0x00007ff7fda4b4b8\u003e":"tag:\"rank\""},"user_query":{"#\u003cMathWorks::Search::Field:0x00007ff7fda4b4b8\u003e":"tag:\"rank\""},"queried_facets":{}},"query_backend":{"connection":{"configuration":{"index_url":"http://index-op-v2/solr/","query_url":"http://search-op-v2/solr/","direct_access_index_urls":["http://index-op-v2/solr/"],"direct_access_query_urls":["http://search-op-v2/solr/"],"timeout":10,"vhost":"search","exchange":"search.topic","heartbeat":30,"pre_index_mode":false,"host":"rabbitmq-eks","port":5672,"username":"cody-search","password":"78X075ddcV44","virtual_host":"search","indexer":"amqp","http_logging":"true","core":"cody"},"query_connection":{"uri":"http://search-op-v2/solr/cody/","proxy":null,"connection":{"parallel_manager":null,"headers":{"User-Agent":"Faraday v1.0.1"},"params":{},"options":{"params_encoder":"Faraday::FlatParamsEncoder","proxy":null,"bind":null,"timeout":null,"open_timeout":null,"read_timeout":null,"write_timeout":null,"boundary":null,"oauth":null,"context":null,"on_data":null},"ssl":{"verify":true,"ca_file":null,"ca_path":null,"verify_mode":null,"cert_store":null,"client_cert":null,"client_key":null,"certificate":null,"private_key":null,"verify_depth":null,"version":null,"min_version":null,"max_version":null},"default_parallel_manager":null,"builder":{"adapter":{"name":"Faraday::Adapter::NetHttp","args":[],"block":null},"handlers":[{"name":"Faraday::Response::RaiseError","args":[],"block":null}],"app":{"app":{"ssl_cert_store":{"verify_callback":null,"error":null,"error_string":null,"chain":null,"time":null},"app":{},"connection_options":{},"config_block":null}}},"url_prefix":"http://search-op-v2/solr/cody/","manual_proxy":false,"proxy":null},"update_format":"RSolr::JSON::Generator","update_path":"update","options":{"url":"http://search-op-v2/solr/cody"}}},"query":{"params":{"per_page":50,"term":"tag:\"rank\"","current_player":null,"sort":"map(difficulty_value,0,0,999) asc"},"parser":"MathWorks::Search::Solr::QueryParser","directives":{"term":{"directives":{"tag":[["tag:\"rank\"","","\"","rank","\""]]}}},"facets":{"#\u003cMathWorks::Search::Field:0x00007ff7fda4b418\u003e":null,"#\u003cMathWorks::Search::Field:0x00007ff7fda4b378\u003e":null},"filters":{"#\u003cMathWorks::Search::Field:0x00007ff7fda4aab8\u003e":"\"cody:problem\""},"fields":{"#\u003cMathWorks::Search::Field:0x00007ff7fda4b698\u003e":1,"#\u003cMathWorks::Search::Field:0x00007ff7fda4b5f8\u003e":50,"#\u003cMathWorks::Search::Field:0x00007ff7fda4b558\u003e":"map(difficulty_value,0,0,999) asc","#\u003cMathWorks::Search::Field:0x00007ff7fda4b4b8\u003e":"tag:\"rank\""},"user_query":{"#\u003cMathWorks::Search::Field:0x00007ff7fda4b4b8\u003e":"tag:\"rank\""},"queried_facets":{}},"options":{"fields":["id","difficulty_rating"]},"join":" "},"results":[{"id":47508,"difficulty_rating":"easy"},{"id":1134,"difficulty_rating":"easy-medium"},{"id":42762,"difficulty_rating":"easy-medium"},{"id":1088,"difficulty_rating":"easy-medium"}]}}