{"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":2447,"title":"Musical Note Interval 1 - Diatonic Scale","description":"Assuming a simple diatonic C scale, calculate the interval (integer) between two notes (provided as strings). By applying numbers to the notes of the scale (C,D,E,F,G,A,B,C = 1,2,3,4,5,6,7,8), intervals can be calculated. Because a unison is defined as one rather than zero, you add one to the numerical difference. The intervals are defined as:\r\n\r\nC - C: perfect unison, 1\r\n\r\nC - D: major second, 2\r\n\r\nC - E: major third, 3\r\n\r\nC - F: perfect fourth, 4\r\n\r\nC - G: perfect fifth, 5\r\n\r\nC - A: major sixth, 6\r\n\r\nC - B: major seventh, 7\r\n\r\nFor example, if the input is {'C','G'} the output will be a perfect fifth: 5-1+1=5. For input {'E','A'} the output will be a perfect fourth: 6-3+1=4.\r\n\r\nFor intervals that wrap around the scale, add seven to the resulting negative number to obtain the correct interval. For example, for {'A','C'} the output will be a major third: 1-6+1=-4, -4+7=3.","description_html":"\u003cp\u003eAssuming a simple diatonic C scale, calculate the interval (integer) between two notes (provided as strings). By applying numbers to the notes of the scale (C,D,E,F,G,A,B,C = 1,2,3,4,5,6,7,8), intervals can be calculated. Because a unison is defined as one rather than zero, you add one to the numerical difference. The intervals are defined as:\u003c/p\u003e\u003cp\u003eC - C: perfect unison, 1\u003c/p\u003e\u003cp\u003eC - D: major second, 2\u003c/p\u003e\u003cp\u003eC - E: major third, 3\u003c/p\u003e\u003cp\u003eC - F: perfect fourth, 4\u003c/p\u003e\u003cp\u003eC - G: perfect fifth, 5\u003c/p\u003e\u003cp\u003eC - A: major sixth, 6\u003c/p\u003e\u003cp\u003eC - B: major seventh, 7\u003c/p\u003e\u003cp\u003eFor example, if the input is {'C','G'} the output will be a perfect fifth: 5-1+1=5. For input {'E','A'} the output will be a perfect fourth: 6-3+1=4.\u003c/p\u003e\u003cp\u003eFor intervals that wrap around the scale, add seven to the resulting negative number to obtain the correct interval. For example, for {'A','C'} the output will be a major third: 1-6+1=-4, -4+7=3.\u003c/p\u003e","function_template":"function interval = note_interval(notes)\r\n interval = 0;\r\nend","test_suite":"%%\r\nnotes = {'C','G'};\r\ninterval = 5;\r\nassert(isequal(note_interval(notes),interval))\r\n\r\n%%\r\nnotes = {'C','E'};\r\ninterval = 3;\r\nassert(isequal(note_interval(notes),interval))\r\n\r\n%%\r\nnotes = {'G','C'};\r\ninterval = 4;\r\nassert(isequal(note_interval(notes),interval))\r\n\r\n%%\r\nnotes = {'C','B'};\r\ninterval = 7;\r\nassert(isequal(note_interval(notes),interval))\r\n\r\n%%\r\nnotes = {'C','C'};\r\ninterval = 1;\r\nassert(isequal(note_interval(notes),interval))\r\n\r\n%%\r\nnotes = {'E','A'};\r\ninterval = 4;\r\nassert(isequal(note_interval(notes),interval))\r\n\r\n%%\r\nnotes = {'D','C'};\r\ninterval = 7;\r\nassert(isequal(note_interval(notes),interval))\r\n\r\n%%\r\nnotes = {'D','E'};\r\ninterval = 2;\r\nassert(isequal(note_interval(notes),interval))\r\n\r\n%%\r\nnotes = {'A','C'};\r\ninterval = 3;\r\nassert(isequal(note_interval(notes),interval))\r\n\r\n%%\r\nnotes = {'C','A'};\r\ninterval = 6;\r\nassert(isequal(note_interval(notes),interval))\r\n\r\n%%\r\nnotes = {'C','E'};\r\ninterval = 3;\r\nassert(isequal(note_interval(notes),interval))\r\n\r\n%%\r\nnotes = {'E','C'};\r\ninterval = 6;\r\nassert(isequal(note_interval(notes),interval))","published":true,"deleted":false,"likes_count":2,"comments_count":0,"created_by":26769,"edited_by":null,"edited_at":null,"deleted_by":null,"deleted_at":null,"solvers_count":43,"test_suite_updated_at":null,"rescore_all_solutions":false,"group_id":1,"created_at":"2014-07-18T15:06:07.000Z","updated_at":"2026-05-28T03:04:57.000Z","published_at":"2014-07-18T15:06:07.000Z","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\u003eAssuming a simple diatonic C scale, calculate the interval (integer) between two notes (provided as strings). By applying numbers to the notes of the scale (C,D,E,F,G,A,B,C = 1,2,3,4,5,6,7,8), intervals can be calculated. Because a unison is defined as one rather than zero, you add one to the numerical difference. The intervals are defined as:\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\u003eC - C: perfect unison, 1\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\u003eC - D: major second, 2\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\u003eC - E: major third, 3\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\u003eC - F: perfect fourth, 4\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\u003eC - G: perfect fifth, 5\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\u003eC - A: major sixth, 6\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\u003eC - B: major seventh, 7\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\u003eFor example, if the input is {'C','G'} the output will be a perfect fifth: 5-1+1=5. For input {'E','A'} the output will be a perfect fourth: 6-3+1=4.\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\u003eFor intervals that wrap around the scale, add seven to the resulting negative number to obtain the correct interval. For example, for {'A','C'} the output will be a major third: 1-6+1=-4, -4+7=3.\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":2447,"title":"Musical Note Interval 1 - Diatonic Scale","description":"Assuming a simple diatonic C scale, calculate the interval (integer) between two notes (provided as strings). By applying numbers to the notes of the scale (C,D,E,F,G,A,B,C = 1,2,3,4,5,6,7,8), intervals can be calculated. Because a unison is defined as one rather than zero, you add one to the numerical difference. The intervals are defined as:\r\n\r\nC - C: perfect unison, 1\r\n\r\nC - D: major second, 2\r\n\r\nC - E: major third, 3\r\n\r\nC - F: perfect fourth, 4\r\n\r\nC - G: perfect fifth, 5\r\n\r\nC - A: major sixth, 6\r\n\r\nC - B: major seventh, 7\r\n\r\nFor example, if the input is {'C','G'} the output will be a perfect fifth: 5-1+1=5. For input {'E','A'} the output will be a perfect fourth: 6-3+1=4.\r\n\r\nFor intervals that wrap around the scale, add seven to the resulting negative number to obtain the correct interval. For example, for {'A','C'} the output will be a major third: 1-6+1=-4, -4+7=3.","description_html":"\u003cp\u003eAssuming a simple diatonic C scale, calculate the interval (integer) between two notes (provided as strings). By applying numbers to the notes of the scale (C,D,E,F,G,A,B,C = 1,2,3,4,5,6,7,8), intervals can be calculated. Because a unison is defined as one rather than zero, you add one to the numerical difference. The intervals are defined as:\u003c/p\u003e\u003cp\u003eC - C: perfect unison, 1\u003c/p\u003e\u003cp\u003eC - D: major second, 2\u003c/p\u003e\u003cp\u003eC - E: major third, 3\u003c/p\u003e\u003cp\u003eC - F: perfect fourth, 4\u003c/p\u003e\u003cp\u003eC - G: perfect fifth, 5\u003c/p\u003e\u003cp\u003eC - A: major sixth, 6\u003c/p\u003e\u003cp\u003eC - B: major seventh, 7\u003c/p\u003e\u003cp\u003eFor example, if the input is {'C','G'} the output will be a perfect fifth: 5-1+1=5. For input {'E','A'} the output will be a perfect fourth: 6-3+1=4.\u003c/p\u003e\u003cp\u003eFor intervals that wrap around the scale, add seven to the resulting negative number to obtain the correct interval. For example, for {'A','C'} the output will be a major third: 1-6+1=-4, -4+7=3.\u003c/p\u003e","function_template":"function interval = note_interval(notes)\r\n interval = 0;\r\nend","test_suite":"%%\r\nnotes = {'C','G'};\r\ninterval = 5;\r\nassert(isequal(note_interval(notes),interval))\r\n\r\n%%\r\nnotes = {'C','E'};\r\ninterval = 3;\r\nassert(isequal(note_interval(notes),interval))\r\n\r\n%%\r\nnotes = {'G','C'};\r\ninterval = 4;\r\nassert(isequal(note_interval(notes),interval))\r\n\r\n%%\r\nnotes = {'C','B'};\r\ninterval = 7;\r\nassert(isequal(note_interval(notes),interval))\r\n\r\n%%\r\nnotes = {'C','C'};\r\ninterval = 1;\r\nassert(isequal(note_interval(notes),interval))\r\n\r\n%%\r\nnotes = {'E','A'};\r\ninterval = 4;\r\nassert(isequal(note_interval(notes),interval))\r\n\r\n%%\r\nnotes = {'D','C'};\r\ninterval = 7;\r\nassert(isequal(note_interval(notes),interval))\r\n\r\n%%\r\nnotes = {'D','E'};\r\ninterval = 2;\r\nassert(isequal(note_interval(notes),interval))\r\n\r\n%%\r\nnotes = {'A','C'};\r\ninterval = 3;\r\nassert(isequal(note_interval(notes),interval))\r\n\r\n%%\r\nnotes = {'C','A'};\r\ninterval = 6;\r\nassert(isequal(note_interval(notes),interval))\r\n\r\n%%\r\nnotes = {'C','E'};\r\ninterval = 3;\r\nassert(isequal(note_interval(notes),interval))\r\n\r\n%%\r\nnotes = {'E','C'};\r\ninterval = 6;\r\nassert(isequal(note_interval(notes),interval))","published":true,"deleted":false,"likes_count":2,"comments_count":0,"created_by":26769,"edited_by":null,"edited_at":null,"deleted_by":null,"deleted_at":null,"solvers_count":43,"test_suite_updated_at":null,"rescore_all_solutions":false,"group_id":1,"created_at":"2014-07-18T15:06:07.000Z","updated_at":"2026-05-28T03:04:57.000Z","published_at":"2014-07-18T15:06:07.000Z","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\u003eAssuming a simple diatonic C scale, calculate the interval (integer) between two notes (provided as strings). By applying numbers to the notes of the scale (C,D,E,F,G,A,B,C = 1,2,3,4,5,6,7,8), intervals can be calculated. Because a unison is defined as one rather than zero, you add one to the numerical difference. The intervals are defined as:\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\u003eC - C: perfect unison, 1\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\u003eC - D: major second, 2\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\u003eC - E: major third, 3\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\u003eC - F: perfect fourth, 4\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\u003eC - G: perfect fifth, 5\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\u003eC - A: major sixth, 6\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\u003eC - B: major seventh, 7\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\u003eFor example, if the input is {'C','G'} the output will be a perfect fifth: 5-1+1=5. For input {'E','A'} the output will be a perfect fourth: 6-3+1=4.\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\u003eFor intervals that wrap around the scale, add seven to the resulting negative number to obtain the correct interval. For example, for {'A','C'} the output will be a major third: 1-6+1=-4, -4+7=3.\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:\"note\"","page":1,"per_page":50,"sort":"map(difficulty_value,0,0,999) asc"}}