{"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":926,"title":"Unique: Speed Enhancement for uint(8,16,32)","description":"This Speed Performance Challenge is to optimize Unique for processing uint8/uint16/uint32 variables.\r\n\r\n*Input:* A (column vector of uint8/uint16/uint32)\r\n\r\n*Output:* B (column vector A processed by unique \"like\" function)\r\n\r\n*Scoring:* Cumulative time, in msec, of \"unique\" processing of three medium size arrays.\r\n\r\n\r\nExamples:\r\n[5;4;3;2;2;1] returns [1;2;3;4;5], and Fast\r\n\r\n\r\nHint: Help Unique, Legacy, Options\r\n\r\n","description_html":"\u003cp\u003eThis Speed Performance Challenge is to optimize Unique for processing uint8/uint16/uint32 variables.\u003c/p\u003e\u003cp\u003e\u003cb\u003eInput:\u003c/b\u003e A (column vector of uint8/uint16/uint32)\u003c/p\u003e\u003cp\u003e\u003cb\u003eOutput:\u003c/b\u003e B (column vector A processed by unique \"like\" function)\u003c/p\u003e\u003cp\u003e\u003cb\u003eScoring:\u003c/b\u003e Cumulative time, in msec, of \"unique\" processing of three medium size arrays.\u003c/p\u003e\u003cp\u003eExamples:\r\n[5;4;3;2;2;1] returns [1;2;3;4;5], and Fast\u003c/p\u003e\u003cp\u003eHint: Help Unique, Legacy, Options\u003c/p\u003e","function_template":"function y = unique_fast(x)\r\n  y = unique(x);\r\nend","test_suite":"%%\r\nfeval(@assignin,'caller','score',0);\r\n%%\r\nx8=randi(255,1000000,5,'uint8');\r\n\r\nx16=randi(2^16,1000000,4,'uint16');\r\n\r\nx32=randi(2^32,3000000,1,'uint32');\r\n\r\nfor i=1:5 % Warmup Calls to get valid timing\r\n x8w=unique_fast(x8);\r\nend\r\n\r\nta=clock;\r\n%tic\r\n x8u=unique_fast(x8);\r\n%toc\r\n%tic\r\n x16u=unique_fast(x16);\r\n%toc\r\n%tic\r\n x32u=unique_fast(x32);\r\n%toc\r\nt1=etime(clock,ta)*1000;\r\n\r\nassert(isequal(x8u,unique(x8)))\r\nassert(isequal(x16u,unique(x16)))\r\nassert(isequal(x32u,unique(x32)))\r\n\r\nt2=min(2000,t1); % unique scores 2000 msec\r\nfeval(@assignin,'caller','score',floor(t2));\r\n","published":true,"deleted":false,"likes_count":2,"comments_count":0,"created_by":3097,"edited_by":null,"edited_at":null,"deleted_by":null,"deleted_at":null,"solvers_count":27,"test_suite_updated_at":null,"rescore_all_solutions":false,"group_id":1,"created_at":"2012-08-30T03:48:18.000Z","updated_at":"2026-05-26T05:13:11.000Z","published_at":"2012-08-30T04:20:02.000Z","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 Speed Performance Challenge is to optimize Unique for processing uint8/uint16/uint32 variables.\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:rPr\u003e\u003cw:b/\u003e\u003c/w:rPr\u003e\u003cw:t\u003eInput:\u003c/w:t\u003e\u003c/w:r\u003e\u003cw:r\u003e\u003cw:t\u003e A (column vector of uint8/uint16/uint32)\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:rPr\u003e\u003cw:b/\u003e\u003c/w:rPr\u003e\u003cw:t\u003eOutput:\u003c/w:t\u003e\u003c/w:r\u003e\u003cw:r\u003e\u003cw:t\u003e B (column vector A processed by unique \\\"like\\\" function)\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:rPr\u003e\u003cw:b/\u003e\u003c/w:rPr\u003e\u003cw:t\u003eScoring:\u003c/w:t\u003e\u003c/w:r\u003e\u003cw:r\u003e\u003cw:t\u003e Cumulative time, in msec, of \\\"unique\\\" processing of three medium size arrays.\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: [5;4;3;2;2;1] returns [1;2;3;4;5], and Fast\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\u003eHint: Help Unique, Legacy, Options\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":926,"title":"Unique: Speed Enhancement for uint(8,16,32)","description":"This Speed Performance Challenge is to optimize Unique for processing uint8/uint16/uint32 variables.\r\n\r\n*Input:* A (column vector of uint8/uint16/uint32)\r\n\r\n*Output:* B (column vector A processed by unique \"like\" function)\r\n\r\n*Scoring:* Cumulative time, in msec, of \"unique\" processing of three medium size arrays.\r\n\r\n\r\nExamples:\r\n[5;4;3;2;2;1] returns [1;2;3;4;5], and Fast\r\n\r\n\r\nHint: Help Unique, Legacy, Options\r\n\r\n","description_html":"\u003cp\u003eThis Speed Performance Challenge is to optimize Unique for processing uint8/uint16/uint32 variables.\u003c/p\u003e\u003cp\u003e\u003cb\u003eInput:\u003c/b\u003e A (column vector of uint8/uint16/uint32)\u003c/p\u003e\u003cp\u003e\u003cb\u003eOutput:\u003c/b\u003e B (column vector A processed by unique \"like\" function)\u003c/p\u003e\u003cp\u003e\u003cb\u003eScoring:\u003c/b\u003e Cumulative time, in msec, of \"unique\" processing of three medium size arrays.\u003c/p\u003e\u003cp\u003eExamples:\r\n[5;4;3;2;2;1] returns [1;2;3;4;5], and Fast\u003c/p\u003e\u003cp\u003eHint: Help Unique, Legacy, Options\u003c/p\u003e","function_template":"function y = unique_fast(x)\r\n  y = unique(x);\r\nend","test_suite":"%%\r\nfeval(@assignin,'caller','score',0);\r\n%%\r\nx8=randi(255,1000000,5,'uint8');\r\n\r\nx16=randi(2^16,1000000,4,'uint16');\r\n\r\nx32=randi(2^32,3000000,1,'uint32');\r\n\r\nfor i=1:5 % Warmup Calls to get valid timing\r\n x8w=unique_fast(x8);\r\nend\r\n\r\nta=clock;\r\n%tic\r\n x8u=unique_fast(x8);\r\n%toc\r\n%tic\r\n x16u=unique_fast(x16);\r\n%toc\r\n%tic\r\n x32u=unique_fast(x32);\r\n%toc\r\nt1=etime(clock,ta)*1000;\r\n\r\nassert(isequal(x8u,unique(x8)))\r\nassert(isequal(x16u,unique(x16)))\r\nassert(isequal(x32u,unique(x32)))\r\n\r\nt2=min(2000,t1); % unique scores 2000 msec\r\nfeval(@assignin,'caller','score',floor(t2));\r\n","published":true,"deleted":false,"likes_count":2,"comments_count":0,"created_by":3097,"edited_by":null,"edited_at":null,"deleted_by":null,"deleted_at":null,"solvers_count":27,"test_suite_updated_at":null,"rescore_all_solutions":false,"group_id":1,"created_at":"2012-08-30T03:48:18.000Z","updated_at":"2026-05-26T05:13:11.000Z","published_at":"2012-08-30T04:20:02.000Z","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 Speed Performance Challenge is to optimize Unique for processing uint8/uint16/uint32 variables.\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:rPr\u003e\u003cw:b/\u003e\u003c/w:rPr\u003e\u003cw:t\u003eInput:\u003c/w:t\u003e\u003c/w:r\u003e\u003cw:r\u003e\u003cw:t\u003e A (column vector of uint8/uint16/uint32)\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:rPr\u003e\u003cw:b/\u003e\u003c/w:rPr\u003e\u003cw:t\u003eOutput:\u003c/w:t\u003e\u003c/w:r\u003e\u003cw:r\u003e\u003cw:t\u003e B (column vector A processed by unique \\\"like\\\" function)\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:rPr\u003e\u003cw:b/\u003e\u003c/w:rPr\u003e\u003cw:t\u003eScoring:\u003c/w:t\u003e\u003c/w:r\u003e\u003cw:r\u003e\u003cw:t\u003e Cumulative time, in msec, of \\\"unique\\\" processing of three medium size arrays.\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: [5;4;3;2;2;1] returns [1;2;3;4;5], and Fast\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\u003eHint: Help Unique, Legacy, Options\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":"medium","count":1,"selected":false}]],"term":"tag:\"legacy\"","page":1,"per_page":50,"sort":"map(difficulty_value,0,0,999) asc"}}