{"group":{"id":1,"name":"Community","lockable":false,"created_at":"2012-01-18T18:02:15.000Z","updated_at":"2026-04-06T14:01:22.000Z","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":"2026-04-06T00:00:00.000Z","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":58254,"title":"Find the mean of the magic x","description":"Given a x term, find the magic x, then find the mean/average of any one row or column.","description_html":"\u003cdiv style = \"text-align: start; line-height: 20.44px; 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: none solid rgb(0, 0, 0); white-space: normal; \"\u003e\u003cdiv style=\"block-size: 21px; display: block; min-width: 0px; padding-block-start: 0px; padding-top: 0px; perspective-origin: 406.5px 10.5px; transform-origin: 406.5px 10.5px; vertical-align: baseline; \"\u003e\u003cdiv style=\"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: 383.494px 10.5px; text-align: left; transform-origin: 383.503px 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: 0px 0px; transform-origin: 0px 0px; \"\u003e\u003cspan style=\"\"\u003eGiven a x term, find the magic x, then find the mean/average of any one row or column.\u003c/span\u003e\u003c/span\u003e\u003c/div\u003e\u003c/div\u003e\u003c/div\u003e","function_template":"function y = mean_magic(x)\r\ny = x;\r\n","test_suite":"%%\r\nx = 5;\r\ny_correct = 13;\r\nassert(isequal(mean_magic(x),y_correct))\r\n%%\r\nx = 15;\r\ny_correct = 113;\r\nassert(isequal(mean_magic(x),y_correct))\r\n%%\r\nx = 12;\r\ny_correct = 72.5;\r\nassert(isequal(mean_magic(x),y_correct))\r\n%%\r\nx = 22;\r\ny_correct = 242.5;\r\nassert(isequal(mean_magic(x),y_correct))","published":true,"deleted":false,"likes_count":0,"comments_count":0,"created_by":3227359,"edited_by":3227359,"edited_at":"2023-05-03T16:41:31.000Z","deleted_by":null,"deleted_at":null,"solvers_count":23,"test_suite_updated_at":"2023-05-03T16:41:31.000Z","rescore_all_solutions":false,"group_id":1,"created_at":"2023-05-03T14:54:47.000Z","updated_at":"2026-04-05T10:11:27.000Z","published_at":"2023-05-03T14:54:47.000Z","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 x term, find the magic x, then find the mean/average of any one row or column.\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\"}]}"},{"id":54275,"title":"Get twenty-four","description":"Inpur four integers in 1 to 10, you may use plus, minus, multiply and divid to get 24. Note that every integer should be used once and only once. Brackets are of no limit, and the result should exactly be 24 once you calculate by hand. (Calculation in computer will lead to a tolerance to the computer precision.) \r\nYou need to return a format and a vector with the same four integers, such that you can print the expression.\r\nE.g., input                            x = [5 5 7 7]\r\n        you may return            f  = '(%d*%d)-(%d/%d)'\r\n                     and                 z = [5 5 7 7]\r\n      so  24 is obatined by     eval(sprintf(f,z)).\r\n     The answer is not necessary unique, e.g., other acceptable answers are\r\n                                            f  = '(%d*%d)-(%d*%d)'  \r\n                                            z =  [7 7 5 5]\r\n                   and                   f = '(%d-%d)*(%d+%d)'\r\n                                            z = [7 5 7 5]","description_html":"\u003cdiv style = \"text-align: start; line-height: 20.44px; 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: none solid rgb(0, 0, 0); white-space: normal; \"\u003e\u003cdiv style=\"block-size: 363px; display: block; min-width: 0px; padding-block-start: 0px; padding-top: 0px; perspective-origin: 407px 181.5px; transform-origin: 407px 181.5px; vertical-align: baseline; \"\u003e\u003cdiv style=\"block-size: 63px; 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 31.5px; text-align: left; transform-origin: 384px 31.5px; white-space-collapse: preserve; 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: 0px 0px; transform-origin: 0px 0px; unicode-bidi: normal; \"\u003e\u003cspan style=\"\"\u003eInpur four integers in 1 to 10, you may use plus, minus, multiply and divid to get 24. Note that every integer should be used once and only once. Brackets are of no limit, and the result should exactly be 24 once you calculate by hand. (Calculation in computer will lead to a tolerance to the computer precision.) \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-collapse: preserve; 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: 0px 0px; transform-origin: 0px 0px; unicode-bidi: normal; \"\u003e\u003cspan style=\"\"\u003eYou need to return a format and a vector with the same four integers, such that you can print the expression.\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-collapse: preserve; 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: 0px 0px; transform-origin: 0px 0px; unicode-bidi: normal; \"\u003e\u003cspan style=\"\"\u003eE.g., input                            x = [5 5 7 7]\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-collapse: preserve; 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: 0px 0px; transform-origin: 0px 0px; unicode-bidi: normal; \"\u003e\u003cspan style=\"\"\u003e        you may return            f  = '(%d*%d)-(%d/%d)'\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-collapse: preserve; 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: 0px 0px; transform-origin: 0px 0px; unicode-bidi: normal; \"\u003e\u003cspan style=\"\"\u003e                     and                 z = [5 5 7 7]\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-collapse: preserve; 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: 0px 0px; transform-origin: 0px 0px; unicode-bidi: normal; \"\u003e\u003cspan style=\"\"\u003e      so  24 is obatined by     eval(sprintf(f,z)).\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-collapse: preserve; 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: 0px 0px; transform-origin: 0px 0px; unicode-bidi: normal; \"\u003e\u003cspan style=\"\"\u003e     The answer is not necessary unique, e.g., other acceptable answers are\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-collapse: preserve; 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: 0px 0px; transform-origin: 0px 0px; unicode-bidi: normal; \"\u003e\u003cspan style=\"\"\u003e                                            f  = '(%d*%d)-(%d*%d)'  \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-collapse: preserve; 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: 0px 0px; transform-origin: 0px 0px; unicode-bidi: normal; \"\u003e\u003cspan style=\"\"\u003e                                            z =  [7 7 5 5]\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-collapse: preserve; 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: 0px 0px; transform-origin: 0px 0px; unicode-bidi: normal; \"\u003e\u003cspan style=\"\"\u003e                   and                   f = '(%d-%d)*(%d+%d)'\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-collapse: preserve; 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: 0px 0px; transform-origin: 0px 0px; unicode-bidi: normal; \"\u003e\u003cspan style=\"\"\u003e                                            z = [7 5 7 5]\u003c/span\u003e\u003c/span\u003e\u003c/div\u003e\u003c/div\u003e\u003c/div\u003e","function_template":"function [f,z] = get24(x)\r\n  z = 23;\r\n  f = '(%d%d+%s%s)'\r\nend","test_suite":"%%\r\nx = [1 2 3 4];\r\ntry \r\n    [f,z] = get24(x);\r\n    s = sprintf(f,z); s(s\u003e'9'|s\u003c'0')=' '; assert(length(str2num(s))==4);    \r\n    assert(ischar(f));\r\n    assert(all( sort(z)==sort(x) ));\r\n    assert(length(f(f=='-'|f=='+'|f=='*'|f=='/'))==3);\r\n    assert( abs( eval(sprintf(f,z))-24 )\u003c=1e-8 );\r\n    w = f(f~='('\u0026f~=')'\u0026f~='+'\u0026f~='-'\u0026f~='*'\u0026f~='/'\u0026f~='%'\u0026f~='s'\u0026f~='d');\r\n    assert(isempty(w),'unusual format character!');\r\ncatch\r\n    assert(false,'no result or something wrong!');\r\nend\r\n%%\r\nx = [6 9 9 10];\r\ntry \r\n    [f,z] = get24(x);\r\n    s = sprintf(f,z); s(s\u003e=9'|s\u003c'0')=' '; assert(length(str2num(s))==4);    \r\n    assert(ischar(f));\r\n    assert(all( sort(z)==sort(x) ));\r\n    assert(length(f(f=='-'|f=='+'|f=='*'|f=='/'))==3);\r\n    assert( abs( eval(sprintf(f,z))-24 )\u003c=1e-8 );\r\n    w = f(f~='('\u0026f~=')'\u0026f~='+'\u0026f~='-'\u0026f~='*'\u0026f~='/'\u0026f~='%'\u0026f~='s'\u0026f~='d');\r\n    assert(isempty(w),'unusual format character!');\r\ncatch\r\n    assert(false,'no result or something wrong!');\r\nend\r\n%%\r\nx = [4 4 10 10];\r\ntry \r\n    [f,z] = get24(x);\r\n    s = sprintf(f,z); s(s\u003e'9'|s\u003c'0')=' '; assert(length(str2num(s))==4);    \r\n    assert(ischar(f));\r\n    assert(all( sort(z)==sort(x) ));\r\n    assert(length(f(f=='-'|f=='+'|f=='*'|f=='/'))==3);\r\n    assert( abs( eval(sprintf(f,z))-24 )\u003c=1e-8 );\r\n    w = f(f~='('\u0026f~=')'\u0026f~='+'\u0026f~='-'\u0026f~='*'\u0026f~='/'\u0026f~='%'\u0026f~='s'\u0026f~='d');\r\n    assert(isempty(w),'unusual format character!');\r\ncatch\r\n    assert(false,'no result or something wrong!');\r\nend\r\n%%\r\nx = [3 3 7 7];\r\ntry \r\n    [f,z] = get24(x);\r\n    s = sprintf(f,z); s(s\u003e'9'|s\u003c'0')=' '; assert(length(str2num(s))==4);    \r\n    assert(ischar(f));\r\n    assert(all( sort(z)==sort(x) ));\r\n    assert(length(f(f=='-'|f=='+'|f=='*'|f=='/'))==3);\r\n    assert( abs( eval(sprintf(f,z))-24 )\u003c=1e-8 );\r\n    w = f(f~='('\u0026f~=')'\u0026f~='+'\u0026f~='-'\u0026f~='*'\u0026f~='/'\u0026f~='%'\u0026f~='s'\u0026f~='d');\r\n    assert(isempty(w),'unusual format character!');\r\ncatch\r\n    assert(false,'no result or something wrong!');\r\nend\r\n%%\r\nx = [1 4 5 6];\r\ntry \r\n    [f,z] = get24(x);\r\n    s = sprintf(f,z); s(s\u003e'9'|s\u003c'0')=' '; assert(length(str2num(s))==4);    \r\n    assert(ischar(f));\r\n    assert(all( sort(z)==sort(x) ));\r\n    assert(length(f(f=='-'|f=='+'|f=='*'|f=='/'))==3);\r\n    assert( abs( eval(sprintf(f,z))-24 )\u003c=1e-8 );\r\n    w = f(f~='('\u0026f~=')'\u0026f~='+'\u0026f~='-'\u0026f~='*'\u0026f~='/'\u0026f~='%'\u0026f~='s'\u0026f~='d');\r\n    assert(isempty(w),'unusual format character!');\r\ncatch\r\n    assert(false,'no result or something wrong!');\r\nend","published":true,"deleted":false,"likes_count":0,"comments_count":2,"created_by":2197980,"edited_by":2197980,"edited_at":"2024-08-29T05:32:43.000Z","deleted_by":null,"deleted_at":null,"solvers_count":2,"test_suite_updated_at":"2024-08-29T05:32:43.000Z","rescore_all_solutions":false,"group_id":1,"created_at":"2022-04-13T12:52:09.000Z","updated_at":"2024-08-29T05:32:43.000Z","published_at":"2022-04-13T12:52:22.000Z","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\u003eInpur four integers in 1 to 10, you may use plus, minus, multiply and divid to get 24. Note that every integer should be used once and only once. Brackets are of no limit, and the result should exactly be 24 once you calculate by hand. (Calculation in computer will lead to a tolerance to the computer precision.) \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\u003eYou need to return a format and a vector with the same four integers, such that you can print the expression.\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\u003eE.g., input                            x = [5 5 7 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\u003e        you may return            f  = '(%d*%d)-(%d/%d)'\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\u003e                     and                 z = [5 5 7 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\u003e      so  24 is obatined by     eval(sprintf(f,z)).\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\u003e     The answer is not necessary unique, e.g., other acceptable answers are\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\u003e                                            f  = '(%d*%d)-(%d*%d)'  \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\u003e                                            z =  [7 7 5 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\u003e                   and                   f = '(%d-%d)*(%d+%d)'\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\u003e                                            z = [7 5 7 5]\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":{"errors":[],"problems":[{"id":58254,"title":"Find the mean of the magic x","description":"Given a x term, find the magic x, then find the mean/average of any one row or column.","description_html":"\u003cdiv style = \"text-align: start; line-height: 20.44px; 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: none solid rgb(0, 0, 0); white-space: normal; \"\u003e\u003cdiv style=\"block-size: 21px; display: block; min-width: 0px; padding-block-start: 0px; padding-top: 0px; perspective-origin: 406.5px 10.5px; transform-origin: 406.5px 10.5px; vertical-align: baseline; \"\u003e\u003cdiv style=\"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: 383.494px 10.5px; text-align: left; transform-origin: 383.503px 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: 0px 0px; transform-origin: 0px 0px; \"\u003e\u003cspan style=\"\"\u003eGiven a x term, find the magic x, then find the mean/average of any one row or column.\u003c/span\u003e\u003c/span\u003e\u003c/div\u003e\u003c/div\u003e\u003c/div\u003e","function_template":"function y = mean_magic(x)\r\ny = x;\r\n","test_suite":"%%\r\nx = 5;\r\ny_correct = 13;\r\nassert(isequal(mean_magic(x),y_correct))\r\n%%\r\nx = 15;\r\ny_correct = 113;\r\nassert(isequal(mean_magic(x),y_correct))\r\n%%\r\nx = 12;\r\ny_correct = 72.5;\r\nassert(isequal(mean_magic(x),y_correct))\r\n%%\r\nx = 22;\r\ny_correct = 242.5;\r\nassert(isequal(mean_magic(x),y_correct))","published":true,"deleted":false,"likes_count":0,"comments_count":0,"created_by":3227359,"edited_by":3227359,"edited_at":"2023-05-03T16:41:31.000Z","deleted_by":null,"deleted_at":null,"solvers_count":23,"test_suite_updated_at":"2023-05-03T16:41:31.000Z","rescore_all_solutions":false,"group_id":1,"created_at":"2023-05-03T14:54:47.000Z","updated_at":"2026-04-05T10:11:27.000Z","published_at":"2023-05-03T14:54:47.000Z","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 x term, find the magic x, then find the mean/average of any one row or column.\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\"}]}"},{"id":54275,"title":"Get twenty-four","description":"Inpur four integers in 1 to 10, you may use plus, minus, multiply and divid to get 24. Note that every integer should be used once and only once. Brackets are of no limit, and the result should exactly be 24 once you calculate by hand. (Calculation in computer will lead to a tolerance to the computer precision.) \r\nYou need to return a format and a vector with the same four integers, such that you can print the expression.\r\nE.g., input                            x = [5 5 7 7]\r\n        you may return            f  = '(%d*%d)-(%d/%d)'\r\n                     and                 z = [5 5 7 7]\r\n      so  24 is obatined by     eval(sprintf(f,z)).\r\n     The answer is not necessary unique, e.g., other acceptable answers are\r\n                                            f  = '(%d*%d)-(%d*%d)'  \r\n                                            z =  [7 7 5 5]\r\n                   and                   f = '(%d-%d)*(%d+%d)'\r\n                                            z = [7 5 7 5]","description_html":"\u003cdiv style = \"text-align: start; line-height: 20.44px; 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: none solid rgb(0, 0, 0); white-space: normal; \"\u003e\u003cdiv style=\"block-size: 363px; display: block; min-width: 0px; padding-block-start: 0px; padding-top: 0px; perspective-origin: 407px 181.5px; transform-origin: 407px 181.5px; vertical-align: baseline; \"\u003e\u003cdiv style=\"block-size: 63px; 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 31.5px; text-align: left; transform-origin: 384px 31.5px; white-space-collapse: preserve; 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: 0px 0px; transform-origin: 0px 0px; unicode-bidi: normal; \"\u003e\u003cspan style=\"\"\u003eInpur four integers in 1 to 10, you may use plus, minus, multiply and divid to get 24. Note that every integer should be used once and only once. Brackets are of no limit, and the result should exactly be 24 once you calculate by hand. (Calculation in computer will lead to a tolerance to the computer precision.) \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-collapse: preserve; 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: 0px 0px; transform-origin: 0px 0px; unicode-bidi: normal; \"\u003e\u003cspan style=\"\"\u003eYou need to return a format and a vector with the same four integers, such that you can print the expression.\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-collapse: preserve; 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: 0px 0px; transform-origin: 0px 0px; unicode-bidi: normal; \"\u003e\u003cspan style=\"\"\u003eE.g., input                            x = [5 5 7 7]\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-collapse: preserve; 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: 0px 0px; transform-origin: 0px 0px; unicode-bidi: normal; \"\u003e\u003cspan style=\"\"\u003e        you may return            f  = '(%d*%d)-(%d/%d)'\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-collapse: preserve; 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: 0px 0px; transform-origin: 0px 0px; unicode-bidi: normal; \"\u003e\u003cspan style=\"\"\u003e                     and                 z = [5 5 7 7]\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-collapse: preserve; 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: 0px 0px; transform-origin: 0px 0px; unicode-bidi: normal; \"\u003e\u003cspan style=\"\"\u003e      so  24 is obatined by     eval(sprintf(f,z)).\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-collapse: preserve; 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: 0px 0px; transform-origin: 0px 0px; unicode-bidi: normal; \"\u003e\u003cspan style=\"\"\u003e     The answer is not necessary unique, e.g., other acceptable answers are\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-collapse: preserve; 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: 0px 0px; transform-origin: 0px 0px; unicode-bidi: normal; \"\u003e\u003cspan style=\"\"\u003e                                            f  = '(%d*%d)-(%d*%d)'  \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-collapse: preserve; 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: 0px 0px; transform-origin: 0px 0px; unicode-bidi: normal; \"\u003e\u003cspan style=\"\"\u003e                                            z =  [7 7 5 5]\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-collapse: preserve; 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: 0px 0px; transform-origin: 0px 0px; unicode-bidi: normal; \"\u003e\u003cspan style=\"\"\u003e                   and                   f = '(%d-%d)*(%d+%d)'\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-collapse: preserve; 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: 0px 0px; transform-origin: 0px 0px; unicode-bidi: normal; \"\u003e\u003cspan style=\"\"\u003e                                            z = [7 5 7 5]\u003c/span\u003e\u003c/span\u003e\u003c/div\u003e\u003c/div\u003e\u003c/div\u003e","function_template":"function [f,z] = get24(x)\r\n  z = 23;\r\n  f = '(%d%d+%s%s)'\r\nend","test_suite":"%%\r\nx = [1 2 3 4];\r\ntry \r\n    [f,z] = get24(x);\r\n    s = sprintf(f,z); s(s\u003e'9'|s\u003c'0')=' '; assert(length(str2num(s))==4);    \r\n    assert(ischar(f));\r\n    assert(all( sort(z)==sort(x) ));\r\n    assert(length(f(f=='-'|f=='+'|f=='*'|f=='/'))==3);\r\n    assert( abs( eval(sprintf(f,z))-24 )\u003c=1e-8 );\r\n    w = f(f~='('\u0026f~=')'\u0026f~='+'\u0026f~='-'\u0026f~='*'\u0026f~='/'\u0026f~='%'\u0026f~='s'\u0026f~='d');\r\n    assert(isempty(w),'unusual format character!');\r\ncatch\r\n    assert(false,'no result or something wrong!');\r\nend\r\n%%\r\nx = [6 9 9 10];\r\ntry \r\n    [f,z] = get24(x);\r\n    s = sprintf(f,z); s(s\u003e=9'|s\u003c'0')=' '; assert(length(str2num(s))==4);    \r\n    assert(ischar(f));\r\n    assert(all( sort(z)==sort(x) ));\r\n    assert(length(f(f=='-'|f=='+'|f=='*'|f=='/'))==3);\r\n    assert( abs( eval(sprintf(f,z))-24 )\u003c=1e-8 );\r\n    w = f(f~='('\u0026f~=')'\u0026f~='+'\u0026f~='-'\u0026f~='*'\u0026f~='/'\u0026f~='%'\u0026f~='s'\u0026f~='d');\r\n    assert(isempty(w),'unusual format character!');\r\ncatch\r\n    assert(false,'no result or something wrong!');\r\nend\r\n%%\r\nx = [4 4 10 10];\r\ntry \r\n    [f,z] = get24(x);\r\n    s = sprintf(f,z); s(s\u003e'9'|s\u003c'0')=' '; assert(length(str2num(s))==4);    \r\n    assert(ischar(f));\r\n    assert(all( sort(z)==sort(x) ));\r\n    assert(length(f(f=='-'|f=='+'|f=='*'|f=='/'))==3);\r\n    assert( abs( eval(sprintf(f,z))-24 )\u003c=1e-8 );\r\n    w = f(f~='('\u0026f~=')'\u0026f~='+'\u0026f~='-'\u0026f~='*'\u0026f~='/'\u0026f~='%'\u0026f~='s'\u0026f~='d');\r\n    assert(isempty(w),'unusual format character!');\r\ncatch\r\n    assert(false,'no result or something wrong!');\r\nend\r\n%%\r\nx = [3 3 7 7];\r\ntry \r\n    [f,z] = get24(x);\r\n    s = sprintf(f,z); s(s\u003e'9'|s\u003c'0')=' '; assert(length(str2num(s))==4);    \r\n    assert(ischar(f));\r\n    assert(all( sort(z)==sort(x) ));\r\n    assert(length(f(f=='-'|f=='+'|f=='*'|f=='/'))==3);\r\n    assert( abs( eval(sprintf(f,z))-24 )\u003c=1e-8 );\r\n    w = f(f~='('\u0026f~=')'\u0026f~='+'\u0026f~='-'\u0026f~='*'\u0026f~='/'\u0026f~='%'\u0026f~='s'\u0026f~='d');\r\n    assert(isempty(w),'unusual format character!');\r\ncatch\r\n    assert(false,'no result or something wrong!');\r\nend\r\n%%\r\nx = [1 4 5 6];\r\ntry \r\n    [f,z] = get24(x);\r\n    s = sprintf(f,z); s(s\u003e'9'|s\u003c'0')=' '; assert(length(str2num(s))==4);    \r\n    assert(ischar(f));\r\n    assert(all( sort(z)==sort(x) ));\r\n    assert(length(f(f=='-'|f=='+'|f=='*'|f=='/'))==3);\r\n    assert( abs( eval(sprintf(f,z))-24 )\u003c=1e-8 );\r\n    w = f(f~='('\u0026f~=')'\u0026f~='+'\u0026f~='-'\u0026f~='*'\u0026f~='/'\u0026f~='%'\u0026f~='s'\u0026f~='d');\r\n    assert(isempty(w),'unusual format character!');\r\ncatch\r\n    assert(false,'no result or something wrong!');\r\nend","published":true,"deleted":false,"likes_count":0,"comments_count":2,"created_by":2197980,"edited_by":2197980,"edited_at":"2024-08-29T05:32:43.000Z","deleted_by":null,"deleted_at":null,"solvers_count":2,"test_suite_updated_at":"2024-08-29T05:32:43.000Z","rescore_all_solutions":false,"group_id":1,"created_at":"2022-04-13T12:52:09.000Z","updated_at":"2024-08-29T05:32:43.000Z","published_at":"2022-04-13T12:52:22.000Z","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\u003eInpur four integers in 1 to 10, you may use plus, minus, multiply and divid to get 24. Note that every integer should be used once and only once. Brackets are of no limit, and the result should exactly be 24 once you calculate by hand. (Calculation in computer will lead to a tolerance to the computer precision.) \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\u003eYou need to return a format and a vector with the same four integers, such that you can print the expression.\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\u003eE.g., input                            x = [5 5 7 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\u003e        you may return            f  = '(%d*%d)-(%d/%d)'\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\u003e                     and                 z = [5 5 7 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\u003e      so  24 is obatined by     eval(sprintf(f,z)).\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\u003e     The answer is not necessary unique, e.g., other acceptable answers are\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\u003e                                            f  = '(%d*%d)-(%d*%d)'  \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\u003e                                            z =  [7 7 5 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\u003e                   and                   f = '(%d-%d)*(%d+%d)'\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\u003e                                            z = [7 5 7 5]\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\"}]}"}],"term":"tag:\"magic 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