{"group":{"id":1,"name":"Community","lockable":false,"created_at":"2012-01-18T18:02:15.000Z","updated_at":"2026-05-26T00:16:20.000Z","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":"2026-05-26T00:00:00.000Z","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":722,"title":"Make a run-length companion vector","description":"Given a vector x, return a vector r that indicates the run length of any value in x. Each element in r shows how many times the corresponding element in x has appeared consecutively.\r\n\r\nExample:\r\n\r\n Input  x = [5 3 3 1 0 9 9 4 4 4 4 5 1 2 2]\r\n Output r = [1 1 2 1 1 1 2 1 2 3 4 1 1 1 2]","description_html":"\u003cp\u003eGiven a vector x, return a vector r that indicates the run length of any value in x. Each element in r shows how many times the corresponding element in x has appeared consecutively.\u003c/p\u003e\u003cp\u003eExample:\u003c/p\u003e\u003cpre\u003e Input  x = [5 3 3 1 0 9 9 4 4 4 4 5 1 2 2]\r\n Output r = [1 1 2 1 1 1 2 1 2 3 4 1 1 1 2]\u003c/pre\u003e","function_template":"function r = run_length(x)\r\n  r = x;\r\nend","test_suite":"%%\r\nx = [5 3 3 1 0 9 9 4 4 4 4 5 1 2 2];\r\nr_correct = [1 1 2 1 1 1 2 1 2 3 4 1 1 1 2];\r\nassert(isequal(run_length(x),r_correct))\r\n\r\n%%\r\nx = ones(1,20);\r\nr_correct = 1:20;\r\nassert(isequal(run_length(x),r_correct))\r\n\r\n%%\r\nx = [1 1 1 2 2 3 4 4 5 5 5];\r\nr_correct = [1 2 3 1 2 1 1 2 1 2 3];\r\nassert(isequal(run_length(x),r_correct))\r\n\r\n%%\r\nx = 1:40;\r\nr_correct = ones(size(x));\r\nassert(isequal(run_length(x),r_correct))\r\n\r\n%%\r\nx = [-34 -17*ones(1,100)];\r\nr_correct = [1 1:100];\r\nassert(isequal(run_length(x),r_correct))","published":true,"deleted":false,"likes_count":9,"comments_count":6,"created_by":7,"edited_by":null,"edited_at":null,"deleted_by":null,"deleted_at":null,"solvers_count":661,"test_suite_updated_at":"2013-07-11T16:34:02.000Z","rescore_all_solutions":false,"group_id":6,"created_at":"2012-05-24T18:41:44.000Z","updated_at":"2026-05-28T10:50:01.000Z","published_at":"2012-06-08T19:08:22.000Z","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\u003eGiven a vector x, return a vector r that indicates the run length of any value in x. Each element in r shows how many times the corresponding element in x has appeared consecutively.\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:\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[ Input  x = [5 3 3 1 0 9 9 4 4 4 4 5 1 2 2]\\n Output r = [1 1 2 1 1 1 2 1 2 3 4 1 1 1 2]]]\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":722,"title":"Make a run-length companion vector","description":"Given a vector x, return a vector r that indicates the run length of any value in x. Each element in r shows how many times the corresponding element in x has appeared consecutively.\r\n\r\nExample:\r\n\r\n Input  x = [5 3 3 1 0 9 9 4 4 4 4 5 1 2 2]\r\n Output r = [1 1 2 1 1 1 2 1 2 3 4 1 1 1 2]","description_html":"\u003cp\u003eGiven a vector x, return a vector r that indicates the run length of any value in x. Each element in r shows how many times the corresponding element in x has appeared consecutively.\u003c/p\u003e\u003cp\u003eExample:\u003c/p\u003e\u003cpre\u003e Input  x = [5 3 3 1 0 9 9 4 4 4 4 5 1 2 2]\r\n Output r = [1 1 2 1 1 1 2 1 2 3 4 1 1 1 2]\u003c/pre\u003e","function_template":"function r = run_length(x)\r\n  r = x;\r\nend","test_suite":"%%\r\nx = [5 3 3 1 0 9 9 4 4 4 4 5 1 2 2];\r\nr_correct = [1 1 2 1 1 1 2 1 2 3 4 1 1 1 2];\r\nassert(isequal(run_length(x),r_correct))\r\n\r\n%%\r\nx = ones(1,20);\r\nr_correct = 1:20;\r\nassert(isequal(run_length(x),r_correct))\r\n\r\n%%\r\nx = [1 1 1 2 2 3 4 4 5 5 5];\r\nr_correct = [1 2 3 1 2 1 1 2 1 2 3];\r\nassert(isequal(run_length(x),r_correct))\r\n\r\n%%\r\nx = 1:40;\r\nr_correct = ones(size(x));\r\nassert(isequal(run_length(x),r_correct))\r\n\r\n%%\r\nx = [-34 -17*ones(1,100)];\r\nr_correct = [1 1:100];\r\nassert(isequal(run_length(x),r_correct))","published":true,"deleted":false,"likes_count":9,"comments_count":6,"created_by":7,"edited_by":null,"edited_at":null,"deleted_by":null,"deleted_at":null,"solvers_count":661,"test_suite_updated_at":"2013-07-11T16:34:02.000Z","rescore_all_solutions":false,"group_id":6,"created_at":"2012-05-24T18:41:44.000Z","updated_at":"2026-05-28T10:50:01.000Z","published_at":"2012-06-08T19:08:22.000Z","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\u003eGiven a vector x, return a vector r that indicates the run length of any value in x. Each element in r shows how many times the corresponding element in x has appeared consecutively.\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:\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[ Input  x = [5 3 3 1 0 9 9 4 4 4 4 5 1 2 2]\\n Output r = [1 1 2 1 1 1 2 1 2 3 4 1 1 1 2]]]\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":"ASEE Challenge","count":1,"selected":false}],[{"value":"medium","count":1,"selected":false}]],"term":"tag:\"best\"","page":1,"per_page":50,"sort":"map(difficulty_value,0,0,999) asc"}}