{"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":1124,"title":"String permutations on phone keyboard","description":"Given a number such as 2639 return all possible string permutations using the phone-keyboard on Problem 1069.\r\ninput = 78\r\noutput = {'pt';'pu';'pv';'qt';'qu';'qv';'rt';'ru';'rv';'st';'su';'sv'}","description_html":"\u003cdiv style = \"text-align: start; line-height: 20.4333px; min-height: 0px; white-space: normal; color: rgb(0, 0, 0); font-family: Menlo, Monaco, Consolas, monospace; font-style: normal; font-size: 14px; font-weight: 400; text-decoration: rgb(0, 0, 0); white-space: normal; \"\u003e\u003cdiv style=\"block-size: 81px; display: block; min-width: 0px; padding-block-start: 0px; padding-top: 0px; perspective-origin: 407px 40.5px; transform-origin: 407px 40.5px; vertical-align: baseline; \"\u003e\u003cdiv style=\"block-size: 21px; font-family: Helvetica, Arial, sans-serif; line-height: 21px; margin-block-end: 9px; margin-block-start: 2px; margin-bottom: 9px; margin-inline-end: 10px; margin-inline-start: 4px; margin-left: 4px; margin-right: 10px; margin-top: 2px; perspective-origin: 384px 10.5px; text-align: left; transform-origin: 384px 10.5px; white-space: pre-wrap; margin-left: 4px; margin-top: 2px; margin-bottom: 9px; margin-right: 10px; \"\u003e\u003cspan style=\"block-size: auto; display: inline; margin-block-end: 0px; margin-block-start: 0px; margin-bottom: 0px; margin-inline-end: 0px; margin-inline-start: 0px; margin-left: 0px; margin-right: 0px; margin-top: 0px; perspective-origin: 310.5px 8px; transform-origin: 310.5px 8px; unicode-bidi: normal; \"\u003e\u003cspan style=\"\"\u003eGiven a number such as 2639 return all possible string permutations using the phone-keyboard on\u003c/span\u003e\u003c/span\u003e\u003cspan style=\"block-size: auto; display: inline; margin-block-end: 0px; margin-block-start: 0px; margin-bottom: 0px; margin-inline-end: 0px; margin-inline-start: 0px; margin-left: 0px; margin-right: 0px; margin-top: 0px; perspective-origin: 2px 8px; transform-origin: 2px 8px; unicode-bidi: normal; \"\u003e\u003cspan style=\"\"\u003e \u003c/span\u003e\u003c/span\u003e\u003ca target='_blank' href = \"/#null\"\u003e\u003cspan style=\"\"\u003e\u003cspan style=\"\"\u003eProblem 1069\u003c/span\u003e\u003c/span\u003e\u003c/a\u003e\u003cspan style=\"block-size: auto; display: inline; margin-block-end: 0px; margin-block-start: 0px; margin-bottom: 0px; margin-inline-end: 0px; margin-inline-start: 0px; margin-left: 0px; margin-right: 0px; margin-top: 0px; perspective-origin: 2px 8px; transform-origin: 2px 8px; unicode-bidi: normal; \"\u003e\u003cspan style=\"\"\u003e.\u003c/span\u003e\u003c/span\u003e\u003c/div\u003e\u003cdiv style=\"block-size: 21px; font-family: Helvetica, Arial, sans-serif; line-height: 21px; margin-block-end: 9px; margin-block-start: 2px; margin-bottom: 9px; margin-inline-end: 10px; margin-inline-start: 4px; margin-left: 4px; margin-right: 10px; margin-top: 2px; perspective-origin: 384px 10.5px; text-align: left; transform-origin: 384px 10.5px; white-space: pre-wrap; margin-left: 4px; margin-top: 2px; margin-bottom: 9px; margin-right: 10px; \"\u003e\u003cspan style=\"block-size: auto; display: inline; margin-block-end: 0px; margin-block-start: 0px; margin-bottom: 0px; margin-inline-end: 0px; margin-inline-start: 0px; margin-left: 0px; margin-right: 0px; margin-top: 0px; perspective-origin: 31.5px 8px; transform-origin: 31.5px 8px; unicode-bidi: normal; \"\u003e\u003cspan style=\"\"\u003einput = 78\u003c/span\u003e\u003c/span\u003e\u003c/div\u003e\u003cdiv style=\"block-size: 21px; font-family: Helvetica, Arial, sans-serif; line-height: 21px; margin-block-end: 9px; margin-block-start: 2px; margin-bottom: 9px; margin-inline-end: 10px; margin-inline-start: 4px; margin-left: 4px; margin-right: 10px; margin-top: 2px; perspective-origin: 384px 10.5px; text-align: left; transform-origin: 384px 10.5px; white-space: pre-wrap; margin-left: 4px; margin-top: 2px; margin-bottom: 9px; margin-right: 10px; \"\u003e\u003cspan style=\"block-size: auto; display: inline; margin-block-end: 0px; margin-block-start: 0px; margin-bottom: 0px; margin-inline-end: 0px; margin-inline-start: 0px; margin-left: 0px; margin-right: 0px; margin-top: 0px; perspective-origin: 171px 8px; transform-origin: 171px 8px; unicode-bidi: normal; \"\u003e\u003cspan style=\"\"\u003eoutput = {'pt';'pu';'pv';'qt';'qu';'qv';'rt';'ru';'rv';'st';'su';'sv'}\u003c/span\u003e\u003c/span\u003e\u003c/div\u003e\u003c/div\u003e\u003c/div\u003e","function_template":"function y = string_perms(x)\r\n  y = x;\r\nend","test_suite":"%%\r\nx = 2639;\r\ny_correct = {'amdw';'amdx';'amdy';'amdz';'amew';'amex';'amey';'amez';'amfw';'amfx';'amfy';'amfz';'andw';'andx';'andy';'andz';'anew';'anex';'aney';'anez';'anfw';'anfx';'anfy';'anfz';'aodw';'aodx';'aody';'aodz';'aoew';'aoex';'aoey';'aoez';'aofw';'aofx';'aofy';'aofz';'bmdw';'bmdx';'bmdy';'bmdz';'bmew';'bmex';'bmey';'bmez';'bmfw';'bmfx';'bmfy';'bmfz';'bndw';'bndx';'bndy';'bndz';'bnew';'bnex';'bney';'bnez';'bnfw';'bnfx';'bnfy';'bnfz';'bodw';'bodx';'body';'bodz';'boew';'boex';'boey';'boez';'bofw';'bofx';'bofy';'bofz';'cmdw';'cmdx';'cmdy';'cmdz';'cmew';'cmex';'cmey';'cmez';'cmfw';'cmfx';'cmfy';'cmfz';'cndw';'cndx';'cndy';'cndz';'cnew';'cnex';'cney';'cnez';'cnfw';'cnfx';'cnfy';'cnfz';'codw';'codx';'cody';'codz';'coew';'coex';'coey';'coez';'cofw';'cofx';'cofy';'cofz';};\r\nassert(isequal(string_perms(x),y_correct))\r\n\r\n%%\r\nx = 2;\r\ny_correct = {'a';'b';'c'};\r\nassert(isequal(string_perms(x),y_correct))\r\n\r\n%%\r\nx=23;\r\ny_correct = {'ad';'ae';'af';'bd';'be';'bf';'cd';'ce';'cf'};\r\nassert(isequal(string_perms(x),y_correct))\r\n\r\n%%\r\nx = 9;\r\ny_correct = {'w';'x';'y';'z'};\r\nassert(isequal(string_perms(x),y_correct))\r\n\r\n","published":true,"deleted":false,"likes_count":1,"comments_count":2,"created_by":8703,"edited_by":223089,"edited_at":"2022-05-08T10:56:07.000Z","deleted_by":null,"deleted_at":null,"solvers_count":25,"test_suite_updated_at":"2022-05-08T10:56:07.000Z","rescore_all_solutions":false,"group_id":1,"created_at":"2012-12-17T16:40:31.000Z","updated_at":"2026-05-26T15:30:12.000Z","published_at":"2012-12-17T16:40:31.000Z","restored_at":null,"restored_by":null,"spam":null,"simulink":false,"admin_reviewed":false,"description_opc":"{\"parts\":[{\"partUri\":\"/matlab/document.xml\",\"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\u003cw:jc w:val=\\\"left\\\"/\u003e\u003c/w:pPr\u003e\u003cw:r\u003e\u003cw:t\u003eGiven a number such as 2639 return all possible string permutations using the phone-keyboard on\u003c/w:t\u003e\u003c/w:r\u003e\u003cw:r\u003e\u003cw:t\u003e \u003c/w:t\u003e\u003c/w:r\u003e\u003cw:hyperlink w:docLocation=\\\"\\\"\u003e\u003cw:r\u003e\u003cw:t\u003eProblem 1069\u003c/w:t\u003e\u003c/w:r\u003e\u003c/w:hyperlink\u003e\u003cw:r\u003e\u003cw:t\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\u003cw:jc w:val=\\\"left\\\"/\u003e\u003c/w:pPr\u003e\u003cw:r\u003e\u003cw:t\u003einput = 78\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\u003eoutput = {'pt';'pu';'pv';'qt';'qu';'qv';'rt';'ru';'rv';'st';'su';'sv'}\u003c/w:t\u003e\u003c/w:r\u003e\u003c/w:p\u003e\u003c/w:body\u003e\u003c/w:document\u003e\",\"relationship\":null}],\"relationships\":[{\"relationshipType\":\"http://schemas.mathworks.com/matlab/code/2013/relationships/document\",\"target\":\"/matlab/document.xml\",\"relationshipId\":\"rId1\"}]}"}],"problem_search":{"problems":[{"id":1124,"title":"String permutations on phone keyboard","description":"Given a number such as 2639 return all possible string permutations using the phone-keyboard on Problem 1069.\r\ninput = 78\r\noutput = {'pt';'pu';'pv';'qt';'qu';'qv';'rt';'ru';'rv';'st';'su';'sv'}","description_html":"\u003cdiv style = \"text-align: start; line-height: 20.4333px; min-height: 0px; white-space: normal; color: rgb(0, 0, 0); font-family: Menlo, Monaco, Consolas, monospace; font-style: normal; font-size: 14px; font-weight: 400; text-decoration: rgb(0, 0, 0); white-space: normal; \"\u003e\u003cdiv style=\"block-size: 81px; display: block; min-width: 0px; padding-block-start: 0px; padding-top: 0px; perspective-origin: 407px 40.5px; transform-origin: 407px 40.5px; vertical-align: baseline; \"\u003e\u003cdiv style=\"block-size: 21px; font-family: Helvetica, Arial, sans-serif; line-height: 21px; margin-block-end: 9px; margin-block-start: 2px; margin-bottom: 9px; margin-inline-end: 10px; margin-inline-start: 4px; margin-left: 4px; margin-right: 10px; margin-top: 2px; perspective-origin: 384px 10.5px; text-align: left; transform-origin: 384px 10.5px; white-space: pre-wrap; margin-left: 4px; margin-top: 2px; margin-bottom: 9px; margin-right: 10px; \"\u003e\u003cspan style=\"block-size: auto; display: inline; margin-block-end: 0px; margin-block-start: 0px; margin-bottom: 0px; margin-inline-end: 0px; margin-inline-start: 0px; margin-left: 0px; margin-right: 0px; margin-top: 0px; perspective-origin: 310.5px 8px; transform-origin: 310.5px 8px; unicode-bidi: normal; \"\u003e\u003cspan style=\"\"\u003eGiven a number such as 2639 return all possible string permutations using the phone-keyboard on\u003c/span\u003e\u003c/span\u003e\u003cspan style=\"block-size: auto; display: inline; margin-block-end: 0px; margin-block-start: 0px; margin-bottom: 0px; margin-inline-end: 0px; margin-inline-start: 0px; margin-left: 0px; margin-right: 0px; margin-top: 0px; perspective-origin: 2px 8px; transform-origin: 2px 8px; unicode-bidi: normal; \"\u003e\u003cspan style=\"\"\u003e \u003c/span\u003e\u003c/span\u003e\u003ca target='_blank' href = \"/#null\"\u003e\u003cspan style=\"\"\u003e\u003cspan style=\"\"\u003eProblem 1069\u003c/span\u003e\u003c/span\u003e\u003c/a\u003e\u003cspan style=\"block-size: auto; display: inline; margin-block-end: 0px; margin-block-start: 0px; margin-bottom: 0px; margin-inline-end: 0px; margin-inline-start: 0px; margin-left: 0px; margin-right: 0px; margin-top: 0px; perspective-origin: 2px 8px; transform-origin: 2px 8px; unicode-bidi: normal; \"\u003e\u003cspan style=\"\"\u003e.\u003c/span\u003e\u003c/span\u003e\u003c/div\u003e\u003cdiv style=\"block-size: 21px; font-family: Helvetica, Arial, sans-serif; line-height: 21px; margin-block-end: 9px; margin-block-start: 2px; margin-bottom: 9px; margin-inline-end: 10px; margin-inline-start: 4px; margin-left: 4px; margin-right: 10px; margin-top: 2px; perspective-origin: 384px 10.5px; text-align: left; transform-origin: 384px 10.5px; white-space: pre-wrap; margin-left: 4px; margin-top: 2px; margin-bottom: 9px; margin-right: 10px; \"\u003e\u003cspan style=\"block-size: auto; display: inline; margin-block-end: 0px; margin-block-start: 0px; margin-bottom: 0px; margin-inline-end: 0px; margin-inline-start: 0px; margin-left: 0px; margin-right: 0px; margin-top: 0px; perspective-origin: 31.5px 8px; transform-origin: 31.5px 8px; unicode-bidi: normal; \"\u003e\u003cspan style=\"\"\u003einput = 78\u003c/span\u003e\u003c/span\u003e\u003c/div\u003e\u003cdiv style=\"block-size: 21px; font-family: Helvetica, Arial, sans-serif; line-height: 21px; margin-block-end: 9px; margin-block-start: 2px; margin-bottom: 9px; margin-inline-end: 10px; margin-inline-start: 4px; margin-left: 4px; margin-right: 10px; margin-top: 2px; perspective-origin: 384px 10.5px; text-align: left; transform-origin: 384px 10.5px; white-space: pre-wrap; margin-left: 4px; margin-top: 2px; margin-bottom: 9px; margin-right: 10px; \"\u003e\u003cspan style=\"block-size: auto; display: inline; margin-block-end: 0px; margin-block-start: 0px; margin-bottom: 0px; margin-inline-end: 0px; margin-inline-start: 0px; margin-left: 0px; margin-right: 0px; margin-top: 0px; perspective-origin: 171px 8px; transform-origin: 171px 8px; unicode-bidi: normal; \"\u003e\u003cspan style=\"\"\u003eoutput = {'pt';'pu';'pv';'qt';'qu';'qv';'rt';'ru';'rv';'st';'su';'sv'}\u003c/span\u003e\u003c/span\u003e\u003c/div\u003e\u003c/div\u003e\u003c/div\u003e","function_template":"function y = string_perms(x)\r\n  y = x;\r\nend","test_suite":"%%\r\nx = 2639;\r\ny_correct = {'amdw';'amdx';'amdy';'amdz';'amew';'amex';'amey';'amez';'amfw';'amfx';'amfy';'amfz';'andw';'andx';'andy';'andz';'anew';'anex';'aney';'anez';'anfw';'anfx';'anfy';'anfz';'aodw';'aodx';'aody';'aodz';'aoew';'aoex';'aoey';'aoez';'aofw';'aofx';'aofy';'aofz';'bmdw';'bmdx';'bmdy';'bmdz';'bmew';'bmex';'bmey';'bmez';'bmfw';'bmfx';'bmfy';'bmfz';'bndw';'bndx';'bndy';'bndz';'bnew';'bnex';'bney';'bnez';'bnfw';'bnfx';'bnfy';'bnfz';'bodw';'bodx';'body';'bodz';'boew';'boex';'boey';'boez';'bofw';'bofx';'bofy';'bofz';'cmdw';'cmdx';'cmdy';'cmdz';'cmew';'cmex';'cmey';'cmez';'cmfw';'cmfx';'cmfy';'cmfz';'cndw';'cndx';'cndy';'cndz';'cnew';'cnex';'cney';'cnez';'cnfw';'cnfx';'cnfy';'cnfz';'codw';'codx';'cody';'codz';'coew';'coex';'coey';'coez';'cofw';'cofx';'cofy';'cofz';};\r\nassert(isequal(string_perms(x),y_correct))\r\n\r\n%%\r\nx = 2;\r\ny_correct = {'a';'b';'c'};\r\nassert(isequal(string_perms(x),y_correct))\r\n\r\n%%\r\nx=23;\r\ny_correct = {'ad';'ae';'af';'bd';'be';'bf';'cd';'ce';'cf'};\r\nassert(isequal(string_perms(x),y_correct))\r\n\r\n%%\r\nx = 9;\r\ny_correct = {'w';'x';'y';'z'};\r\nassert(isequal(string_perms(x),y_correct))\r\n\r\n","published":true,"deleted":false,"likes_count":1,"comments_count":2,"created_by":8703,"edited_by":223089,"edited_at":"2022-05-08T10:56:07.000Z","deleted_by":null,"deleted_at":null,"solvers_count":25,"test_suite_updated_at":"2022-05-08T10:56:07.000Z","rescore_all_solutions":false,"group_id":1,"created_at":"2012-12-17T16:40:31.000Z","updated_at":"2026-05-26T15:30:12.000Z","published_at":"2012-12-17T16:40:31.000Z","restored_at":null,"restored_by":null,"spam":null,"simulink":false,"admin_reviewed":false,"description_opc":"{\"parts\":[{\"partUri\":\"/matlab/document.xml\",\"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\u003cw:jc w:val=\\\"left\\\"/\u003e\u003c/w:pPr\u003e\u003cw:r\u003e\u003cw:t\u003eGiven a number such as 2639 return all possible string permutations using the phone-keyboard on\u003c/w:t\u003e\u003c/w:r\u003e\u003cw:r\u003e\u003cw:t\u003e \u003c/w:t\u003e\u003c/w:r\u003e\u003cw:hyperlink w:docLocation=\\\"\\\"\u003e\u003cw:r\u003e\u003cw:t\u003eProblem 1069\u003c/w:t\u003e\u003c/w:r\u003e\u003c/w:hyperlink\u003e\u003cw:r\u003e\u003cw:t\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\u003cw:jc w:val=\\\"left\\\"/\u003e\u003c/w:pPr\u003e\u003cw:r\u003e\u003cw:t\u003einput = 78\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\u003eoutput = {'pt';'pu';'pv';'qt';'qu';'qv';'rt';'ru';'rv';'st';'su';'sv'}\u003c/w:t\u003e\u003c/w:r\u003e\u003c/w:p\u003e\u003c/w:body\u003e\u003c/w:document\u003e\",\"relationship\":null}],\"relationships\":[{\"relationshipType\":\"http://schemas.mathworks.com/matlab/code/2013/relationships/document\",\"target\":\"/matlab/document.xml\",\"relationshipId\":\"rId1\"}]}"}],"errors":[],"facets":[[],[{"value":"medium","count":1,"selected":false}]],"term":"tag:\"phone\"","page":1,"per_page":50,"sort":"map(difficulty_value,0,0,999) asc"}}