{"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":160,"title":"So many choices","description":"For inputs _n_ and _k_ (in that order), output the number of ways that k objects can be chosen from amongst n distinct objects. [The order of the selected objects is irrelevant.]\r\n\r\nFor example, suppose you have 4 blocks: red, green, blue, yellow. How many ways are there to select 2 of them? There are 6 ways: RG, RB, RY, GB, GY, BY. [Remember the ordering is irrelevant, so GR is equivalent to RG, and therefore does not count as a distinct choice.]\r\n\r\nSo, function(4,2) ---\u003e 6.","description_html":"\u003cp\u003eFor inputs \u003ci\u003en\u003c/i\u003e and \u003ci\u003ek\u003c/i\u003e (in that order), output the number of ways that k objects can be chosen from amongst n distinct objects. [The order of the selected objects is irrelevant.]\u003c/p\u003e\u003cp\u003eFor example, suppose you have 4 blocks: red, green, blue, yellow. How many ways are there to select 2 of them? There are 6 ways: RG, RB, RY, GB, GY, BY. [Remember the ordering is irrelevant, so GR is equivalent to RG, and therefore does not count as a distinct choice.]\u003c/p\u003e\u003cp\u003eSo, function(4,2) ---\u003e 6.\u003c/p\u003e","function_template":"function y = fcn(x)\r\n  y = x;\r\nend","test_suite":"%%\r\nn = 1;\r\nk = 1;\r\ny_correct = 1;\r\nassert(isequal(fcn(n,k),y_correct))\r\n%%\r\nn = 4;\r\nk = 2;\r\ny_correct = 6;\r\nassert(isequal(fcn(n,k),y_correct))\r\n%%\r\nn = 20;\r\nk = 10;\r\ny_correct = 184756;\r\nassert(isequal(fcn(n,k),y_correct))\r\n\r\n","published":true,"deleted":false,"likes_count":3,"comments_count":4,"created_by":39,"edited_by":null,"edited_at":null,"deleted_by":null,"deleted_at":null,"solvers_count":476,"test_suite_updated_at":"2012-01-29T05:15:18.000Z","rescore_all_solutions":false,"group_id":1,"created_at":"2012-01-29T05:15:18.000Z","updated_at":"2026-05-20T14:11:19.000Z","published_at":"2012-02-02T14:11:44.000Z","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\",\"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 inputs\u003c/w:t\u003e\u003c/w:r\u003e\u003cw:r\u003e\u003cw:t\u003e \u003c/w:t\u003e\u003c/w:r\u003e\u003cw:r\u003e\u003cw:rPr\u003e\u003cw:i/\u003e\u003c/w:rPr\u003e\u003cw:t\u003en\u003c/w:t\u003e\u003c/w:r\u003e\u003cw:r\u003e\u003cw:t\u003e and\u003c/w:t\u003e\u003c/w:r\u003e\u003cw:r\u003e\u003cw:t\u003e \u003c/w:t\u003e\u003c/w:r\u003e\u003cw:r\u003e\u003cw:rPr\u003e\u003cw:i/\u003e\u003c/w:rPr\u003e\u003cw:t\u003ek\u003c/w:t\u003e\u003c/w:r\u003e\u003cw:r\u003e\u003cw:t\u003e (in that order), output the number of ways that k objects can be chosen from amongst n distinct objects. [The order of the selected objects is irrelevant.]\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\u003eFor example, suppose you have 4 blocks: red, green, blue, yellow. How many ways are there to select 2 of them? There are 6 ways: RG, RB, RY, GB, GY, BY. [Remember the ordering is irrelevant, so GR is equivalent to RG, and therefore does not count as a distinct choice.]\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\u003eSo, function(4,2) ---\u0026gt; 6.\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":160,"title":"So many choices","description":"For inputs _n_ and _k_ (in that order), output the number of ways that k objects can be chosen from amongst n distinct objects. [The order of the selected objects is irrelevant.]\r\n\r\nFor example, suppose you have 4 blocks: red, green, blue, yellow. How many ways are there to select 2 of them? There are 6 ways: RG, RB, RY, GB, GY, BY. [Remember the ordering is irrelevant, so GR is equivalent to RG, and therefore does not count as a distinct choice.]\r\n\r\nSo, function(4,2) ---\u003e 6.","description_html":"\u003cp\u003eFor inputs \u003ci\u003en\u003c/i\u003e and \u003ci\u003ek\u003c/i\u003e (in that order), output the number of ways that k objects can be chosen from amongst n distinct objects. [The order of the selected objects is irrelevant.]\u003c/p\u003e\u003cp\u003eFor example, suppose you have 4 blocks: red, green, blue, yellow. How many ways are there to select 2 of them? There are 6 ways: RG, RB, RY, GB, GY, BY. [Remember the ordering is irrelevant, so GR is equivalent to RG, and therefore does not count as a distinct choice.]\u003c/p\u003e\u003cp\u003eSo, function(4,2) ---\u003e 6.\u003c/p\u003e","function_template":"function y = fcn(x)\r\n  y = x;\r\nend","test_suite":"%%\r\nn = 1;\r\nk = 1;\r\ny_correct = 1;\r\nassert(isequal(fcn(n,k),y_correct))\r\n%%\r\nn = 4;\r\nk = 2;\r\ny_correct = 6;\r\nassert(isequal(fcn(n,k),y_correct))\r\n%%\r\nn = 20;\r\nk = 10;\r\ny_correct = 184756;\r\nassert(isequal(fcn(n,k),y_correct))\r\n\r\n","published":true,"deleted":false,"likes_count":3,"comments_count":4,"created_by":39,"edited_by":null,"edited_at":null,"deleted_by":null,"deleted_at":null,"solvers_count":476,"test_suite_updated_at":"2012-01-29T05:15:18.000Z","rescore_all_solutions":false,"group_id":1,"created_at":"2012-01-29T05:15:18.000Z","updated_at":"2026-05-20T14:11:19.000Z","published_at":"2012-02-02T14:11:44.000Z","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\",\"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 inputs\u003c/w:t\u003e\u003c/w:r\u003e\u003cw:r\u003e\u003cw:t\u003e \u003c/w:t\u003e\u003c/w:r\u003e\u003cw:r\u003e\u003cw:rPr\u003e\u003cw:i/\u003e\u003c/w:rPr\u003e\u003cw:t\u003en\u003c/w:t\u003e\u003c/w:r\u003e\u003cw:r\u003e\u003cw:t\u003e and\u003c/w:t\u003e\u003c/w:r\u003e\u003cw:r\u003e\u003cw:t\u003e \u003c/w:t\u003e\u003c/w:r\u003e\u003cw:r\u003e\u003cw:rPr\u003e\u003cw:i/\u003e\u003c/w:rPr\u003e\u003cw:t\u003ek\u003c/w:t\u003e\u003c/w:r\u003e\u003cw:r\u003e\u003cw:t\u003e (in that order), output the number of ways that k objects can be chosen from amongst n distinct objects. [The order of the selected objects is irrelevant.]\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\u003eFor example, suppose you have 4 blocks: red, green, blue, yellow. How many ways are there to select 2 of them? There are 6 ways: RG, RB, RY, GB, GY, BY. 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