{"group":{"id":1,"name":"Community","lockable":false,"created_at":"2012-01-18T18:02:15.000Z","updated_at":"2026-06-05T00:10:21.000Z","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":"2026-06-05T00:00:00.000Z","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":44687,"title":"basic matrix operations: rotate and find sum of diagonal elements of the resultant matrix","description":"For given input matrix a, rotate it by 90 degrees and find the sum of the diagonals.\r\n\r\nExample:\r\nInput:\r\n\r\n  a =\r\n\r\n     1     2     3     4\r\n     5     6     7     8\r\n     8    10    12    -2\r\n    -1    -3    -5    -7\r\n\r\nOutput is: \r\n\r\n  20","description_html":"\u003cp\u003eFor given input matrix a, rotate it by 90 degrees and find the sum of the diagonals.\u003c/p\u003e\u003cp\u003eExample:\r\nInput:\u003c/p\u003e\u003cpre class=\"language-matlab\"\u003ea =\r\n\u003c/pre\u003e\u003cpre\u003e     1     2     3     4\r\n     5     6     7     8\r\n     8    10    12    -2\r\n    -1    -3    -5    -7\u003c/pre\u003e\u003cp\u003eOutput is:\u003c/p\u003e\u003cpre class=\"language-matlab\"\u003e20\r\n\u003c/pre\u003e","function_template":"function ans = matrix_manipulation(x)\r\n  \r\nend","test_suite":"%%\r\nx = [1 2 3 4; 5 6 7 8;8 10, 12, -2;-1 -3 -5,-7];\r\ny_correct = 20;\r\nassert(isequal(matrix_manipulation(x),y_correct))\r\n\r\n%%\r\nx = ones(5).*3\r\ny_correct = 15;\r\nassert(isequal(matrix_manipulation(x),y_correct))\r\n\r\n%%\r\na=[3,2,5]\r\nx = [a;a;a];\r\ny_correct = 10;\r\nassert(isequal(matrix_manipulation(x),y_correct))\r\n\r\n%%\r\nx = [-5,25,-10;8,-18,10;-2,7,-1]\r\ny_correct = -30;\r\nassert(isequal(matrix_manipulation(x),y_correct))","published":true,"deleted":false,"likes_count":0,"comments_count":0,"created_by":171559,"edited_by":null,"edited_at":null,"deleted_by":null,"deleted_at":null,"solvers_count":63,"test_suite_updated_at":"2018-06-13T08:54:27.000Z","rescore_all_solutions":false,"group_id":1,"created_at":"2018-06-13T08:49:50.000Z","updated_at":"2026-05-30T00:36:46.000Z","published_at":"2018-06-13T08:54:27.000Z","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\u003eFor given input matrix a, rotate it by 90 degrees and find the sum of the diagonals.\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\u003eExample: Input:\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[a =\\n\\n     1     2     3     4\\n     5     6     7     8\\n     8    10    12    -2\\n    -1    -3    -5    -7]]\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\u003eOutput is:\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[20]]\u003e\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":{"problems":[{"id":44687,"title":"basic matrix operations: rotate and find sum of diagonal elements of the resultant matrix","description":"For given input matrix a, rotate it by 90 degrees and find the sum of the diagonals.\r\n\r\nExample:\r\nInput:\r\n\r\n  a =\r\n\r\n     1     2     3     4\r\n     5     6     7     8\r\n     8    10    12    -2\r\n    -1    -3    -5    -7\r\n\r\nOutput is: \r\n\r\n  20","description_html":"\u003cp\u003eFor given input matrix a, rotate it by 90 degrees and find the sum of the diagonals.\u003c/p\u003e\u003cp\u003eExample:\r\nInput:\u003c/p\u003e\u003cpre class=\"language-matlab\"\u003ea =\r\n\u003c/pre\u003e\u003cpre\u003e     1     2     3     4\r\n     5     6     7     8\r\n     8    10    12    -2\r\n    -1    -3    -5    -7\u003c/pre\u003e\u003cp\u003eOutput is:\u003c/p\u003e\u003cpre class=\"language-matlab\"\u003e20\r\n\u003c/pre\u003e","function_template":"function ans = matrix_manipulation(x)\r\n  \r\nend","test_suite":"%%\r\nx = [1 2 3 4; 5 6 7 8;8 10, 12, -2;-1 -3 -5,-7];\r\ny_correct = 20;\r\nassert(isequal(matrix_manipulation(x),y_correct))\r\n\r\n%%\r\nx = ones(5).*3\r\ny_correct = 15;\r\nassert(isequal(matrix_manipulation(x),y_correct))\r\n\r\n%%\r\na=[3,2,5]\r\nx = [a;a;a];\r\ny_correct = 10;\r\nassert(isequal(matrix_manipulation(x),y_correct))\r\n\r\n%%\r\nx = [-5,25,-10;8,-18,10;-2,7,-1]\r\ny_correct = -30;\r\nassert(isequal(matrix_manipulation(x),y_correct))","published":true,"deleted":false,"likes_count":0,"comments_count":0,"created_by":171559,"edited_by":null,"edited_at":null,"deleted_by":null,"deleted_at":null,"solvers_count":63,"test_suite_updated_at":"2018-06-13T08:54:27.000Z","rescore_all_solutions":false,"group_id":1,"created_at":"2018-06-13T08:49:50.000Z","updated_at":"2026-05-30T00:36:46.000Z","published_at":"2018-06-13T08:54:27.000Z","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\u003eFor given input matrix a, rotate it by 90 degrees and find the sum of the diagonals.\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\u003eExample: Input:\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[a =\\n\\n     1     2     3     4\\n     5     6     7     8\\n     8    10    12    -2\\n    -1    -3    -5    -7]]\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\u003eOutput is:\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[20]]\u003e\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\"}]}"}],"errors":[],"facets":[[],[{"value":"easy","count":1,"selected":false}]],"term":"tag:\"trace\"","page":1,"per_page":50,"sort":"map(difficulty_value,0,0,999) asc"}}