{"group":{"id":1,"name":"Community","lockable":false,"created_at":"2012-01-18T18:02:15.000Z","updated_at":"2025-12-14T01:33:56.000Z","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":"2025-12-14T00:00:00.000Z","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":42307,"title":"Long-digit Subtraction","description":"Suppose you need to subtract a very large integer from another integer. \u003chttp://www.mathworks.com/matlabcentral/cody/problems/563-how-to-add This problem\u003e requires the player to add two long digits, both supplied as strings, and to return the sum as a string. This problem similarly provides two numbers as strings and you must return the difference as a string (a - b = c). The result will always be positive as a will be larger than b. See the test suite for examples.\r\n","description_html":"\u003cp\u003eSuppose you need to subtract a very large integer from another integer. \u003ca href = \"http://www.mathworks.com/matlabcentral/cody/problems/563-how-to-add\"\u003eThis problem\u003c/a\u003e requires the player to add two long digits, both supplied as strings, and to return the sum as a string. This problem similarly provides two numbers as strings and you must return the difference as a string (a - b = c). The result will always be positive as a will be larger than b. See the test suite for examples.\u003c/p\u003e","function_template":"function c = long_digit_subtraction(a,b)\r\n\r\nc = a - b;\r\n\r\nend\r\n","test_suite":"%%\r\na = '99999';\r\nb = '87654';\r\n%----------\r\nc = '12345';\r\nassert(strcmp(long_digit_subtraction(a,b),c))\r\n\r\n%%\r\na = '99999';\r\nb =  '1234';\r\n%----------\r\nc = '98765';\r\nassert(strcmp(long_digit_subtraction(a,b),c))\r\n\r\n%%\r\na = '99999';\r\nb = '98765';\r\n%----------\r\nc =  '1234';\r\nassert(strcmp(long_digit_subtraction(a,b),c))\r\n\r\n%%\r\na = '99999';\r\nb = '90909';\r\n%----------\r\nc =  '9090';\r\nassert(strcmp(long_digit_subtraction(a,b),c))\r\n\r\n%%\r\na = '11111';\r\nb =  '1234';\r\n%----------\r\nc =  '9877';\r\nassert(strcmp(long_digit_subtraction(a,b),c))\r\n\r\n%%\r\na = '10000';\r\nb =     '1';\r\n%----------\r\nc =  '9999';\r\nassert(strcmp(long_digit_subtraction(a,b),c))\r\n\r\n%%\r\na = '10000000';\r\nb =  '9999999';\r\n%-------------\r\nc =        '1';\r\nassert(strcmp(long_digit_subtraction(a,b),c))\r\n\r\n%%\r\na = '100000000000000000000000000000000000000000000000000000000000000000000';\r\nb =                                                                     '1';\r\n%--------------------------------------------------------------------------\r\nc =  '99999999999999999999999999999999999999999999999999999999999999999999';\r\nassert(strcmp(long_digit_subtraction(a,b),c))\r\n\r\n%%\r\na = '2135476542136876516521651162516';\r\nb =  '165267982494266414654661818517';\r\n%------------------------------------\r\nc = '1970208559642610101866989343999';\r\nassert(strcmp(long_digit_subtraction(a,b),c))\r\n\r\n%%\r\na = '1000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000';\r\nb =                                                                                                                                                             '1';\r\n%------------------------------------------------------------------------------------------------------------------------------------------------------------------\r\nc =  '999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999';\r\nassert(strcmp(long_digit_subtraction(a,b),c))\r\n\r\n%%\r\na = '1000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000';\r\nb =                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                             '1';\r\n%------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------\r\nc =  '999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999';\r\nassert(strcmp(long_digit_subtraction(a,b),c))\r\n\r\n%%\r\nswitch randi(4)\r\n\tcase 1\r\n\t\ta = '99999';\r\n\t\tb = '87654';\r\n\t\tc = '12345';\r\n\tcase 2\r\n\t\ta = '99999';\r\n\t\tb =  '1234';\r\n\t\tc = '98765';\r\n\tcase 3\r\n\t\ta = '10000000';\r\n\t\tb =  '9999999';\r\n\t\tc =        '1';\r\n\tcase 4\r\n\t\ta = '99999';\r\n\t\tb = '90909';\r\n\t\tc =  '9090';\r\nend\r\nassert(strcmp(long_digit_subtraction(a,b),c))\r\n\r\n%%\r\nswitch randi(4)\r\n\tcase 1\r\n\t\ta = '99999';\r\n\t\tb = '98765';\r\n\t\tc =  '1234';\r\n\tcase 2\r\n\t\ta = '10000';\r\n\t\tb =     '1';\r\n\t\tc =  '9999';\r\n\tcase 3\r\n\t\ta = '99999';\r\n\t\tb = '87654';\r\n\t\tc = '12345';\r\n\tcase 4\r\n\t\ta = '2135476542136876516521651162516';\r\n\t\tb =  '165267982494266414654661818517';\r\n\t\tc = '1970208559642610101866989343999';\r\nend\r\nassert(strcmp(long_digit_subtraction(a,b),c))\r\n\r\n%%\r\nswitch randi(4)\r\n\tcase 1\r\n\t\ta = '11111';\r\n\t\tb =  '1234';\r\n\t\tc =  '9877';\r\n\tcase 2\r\n\t\ta = '10000000';\r\n\t\tb =  '9999999';\r\n\t\tc =        '1';\r\n\tcase 3\r\n\t\ta = '99999';\r\n\t\tb = '98765';\r\n\t\tc =  '1234';\r\n\tcase 4\r\n\t\ta = '99999';\r\n\t\tb = '87654';\r\n\t\tc = '12345';\r\nend\r\nassert(strcmp(long_digit_subtraction(a,b),c))\r\n","published":true,"deleted":false,"likes_count":0,"comments_count":0,"created_by":26769,"edited_by":null,"edited_at":null,"deleted_by":null,"deleted_at":null,"solvers_count":24,"test_suite_updated_at":null,"rescore_all_solutions":false,"group_id":1,"created_at":"2015-05-13T01:27:00.000Z","updated_at":"2025-11-03T11:24:33.000Z","published_at":"2015-05-13T01:27:00.000Z","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\u003eSuppose you need to subtract a very large integer from another integer.\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=\\\"http://www.mathworks.com/matlabcentral/cody/problems/563-how-to-add\\\"\u003e\u003cw:r\u003e\u003cw:t\u003eThis problem\u003c/w:t\u003e\u003c/w:r\u003e\u003c/w:hyperlink\u003e\u003cw:r\u003e\u003cw:t\u003e requires the player to add two long digits, both supplied as strings, and to return the sum as a string. This problem similarly provides two numbers as strings and you must return the difference as a string (a - b = c). The result will always be positive as a will be larger than b. See the test suite for examples.\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\"}]}"},{"id":963,"title":"We love vectorized solutions.  Problem 1 : remove the row average.","description":"Given a 2-d matrix, remove the row average from each row.  Your solution MUST be vectorized.  The solution will be tested for accuracy AND speed.  Any for loops will make the solution too slow to pass the speed test.\r\n\r\nExample:\r\n\r\n  a = [ 1 2 ; 3 5 ];\r\n  b = remove_average_vectorized(a);\r\n  % b is [ -0.5 0.5 ; -1 1 ];\r\n","description_html":"\u003cp\u003eGiven a 2-d matrix, remove the row average from each row.  Your solution MUST be vectorized.  The solution will be tested for accuracy AND speed.  Any for loops will make the solution too slow to pass the speed test.\u003c/p\u003e\u003cp\u003eExample:\u003c/p\u003e\u003cpre class=\"language-matlab\"\u003ea = [ 1 2 ; 3 5 ];\r\nb = remove_average_vectorized(a);\r\n% b is [ -0.5 0.5 ; -1 1 ];\r\n\u003c/pre\u003e","function_template":"function y = remove_average_vectorized(x)\r\n    % This works but is too slow.\r\n\r\n    for row=1:size(x,1)\r\n      row_average=mean(x(row,:));\r\n      for col=1:size(x,2)\r\n        x(row,col)=x(row,col)-row_average; \r\n      end\r\n    end\r\n  y=x;\r\nend","test_suite":"x = [ 0 1 ; 2 3 ] ;\r\ny_correct = [ -0.5 0.5 ; -0.5 0.5 ] ;\r\ny = remove_average_vectorized(x);\r\nassert(isequal(y,y_correct));\r\n\r\n%% \r\nx = [ 0 1 ; 2 3 ] ;\r\ntimer=tic;\r\ny = remove_average_vectorized(x);\r\nduration=toc(timer)\r\n% You can probably pass this test with a for loop.\r\nassert(duration\u003c0.1,sprintf('Time used %2.3f\\n',duration)); \r\n\r\n%%\r\nx = [ 1:9999 ; 2:10000 ; [ zeros(1,9998) 9999 ]  ];\r\nx = repmat(x,1000,1);\r\ny_correct = [ -4999:1:4999 ; -4999:1:4999 ; [ repmat(-1,1,9998) 9998 ] ];\r\ny_correct = repmat(y_correct,1000,1);\r\ny = remove_average_vectorized(x);\r\nassert(isequal(y,y_correct));\r\n\r\n%%\r\nx = [ 1:9999 ; 2:10000 ; [ zeros(1,9998) 9999 ]  ];\r\nx = repmat(x,1000,1);\r\ntimer=tic;\r\ny = remove_average_vectorized(x);\r\nduration=toc(timer)\r\n% A decent vectorized solution should take around 1 second.\r\nassert(duration\u003c2,sprintf('Time used %2.3f\\n',duration)); ","published":true,"deleted":false,"likes_count":7,"comments_count":12,"created_by":6808,"edited_by":null,"edited_at":null,"deleted_by":null,"deleted_at":null,"solvers_count":884,"test_suite_updated_at":"2012-10-02T05:21:12.000Z","rescore_all_solutions":false,"group_id":12,"created_at":"2012-10-01T06:43:20.000Z","updated_at":"2026-01-19T06:40:50.000Z","published_at":"2012-10-01T07:30:28.000Z","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\u003eGiven a 2-d matrix, remove the row average from each row. Your solution MUST be vectorized. The solution will be tested for accuracy AND speed. Any for loops will make the solution too slow to pass the speed test.\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\u003eExample:\u003c/w:t\u003e\u003c/w:r\u003e\u003c/w:p\u003e\u003cw:p\u003e\u003cw:pPr\u003e\u003cw:pStyle w:val=\\\"code\\\"/\u003e\u003c/w:pPr\u003e\u003cw:r\u003e\u003cw:t\u003e\u003c![CDATA[a = [ 1 2 ; 3 5 ];\\nb = remove_average_vectorized(a);\\n% b is [ -0.5 0.5 ; -1 1 ];]]\u003e\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\"}]}"},{"id":43738,"title":"Negative without '-'","description":"Simple: return a negative number without using the '-' sign.\r\n\r\nThanks to Problem \u003chttps://www.mathworks.com/matlabcentral/cody/problems/813-multiply-2-numbers/solutions/new 813\u003e for help with test suite.","description_html":"\u003cdiv style = \"text-align: start; line-height: 20px; 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: normal; text-decoration: none; white-space: normal; \"\u003e\u003cdiv style=\"display: block; min-width: 0px; padding-top: 0px; transform-origin: 332px 25.5px; vertical-align: baseline; perspective-origin: 332px 25.5px; \"\u003e\u003cdiv style=\"font-family: Helvetica, Arial, sans-serif; line-height: 21px; margin-bottom: 9px; margin-left: 4px; margin-right: 10px; margin-top: 2px; text-align: left; transform-origin: 309px 10.5px; white-space: pre-wrap; perspective-origin: 309px 10.5px; margin-left: 4px; margin-top: 2px; margin-bottom: 9px; margin-right: 10px; \"\u003e\u003cspan style=\"display: inline; margin-bottom: 0px; margin-left: 0px; margin-right: 0px; margin-top: 0px; transform-origin: 0px 0px; perspective-origin: 0px 0px; \"\u003e\u003cspan style=\"\"\u003eSimple: return a negative number without using the '-' sign.\u003c/span\u003e\u003c/span\u003e\u003c/div\u003e\u003cdiv style=\"font-family: Helvetica, Arial, sans-serif; line-height: 21px; margin-bottom: 9px; margin-left: 4px; margin-right: 10px; margin-top: 2px; text-align: left; transform-origin: 309px 10.5px; white-space: pre-wrap; perspective-origin: 309px 10.5px; margin-left: 4px; margin-top: 2px; margin-bottom: 9px; margin-right: 10px; \"\u003e\u003cspan style=\"display: inline; margin-bottom: 0px; margin-left: 0px; margin-right: 0px; margin-top: 0px; transform-origin: 0px 0px; perspective-origin: 0px 0px; \"\u003e\u003cspan style=\"\"\u003eThanks to Problem\u003c/span\u003e\u003c/span\u003e\u003cspan style=\"display: inline; margin-bottom: 0px; margin-left: 0px; margin-right: 0px; margin-top: 0px; transform-origin: 0px 0px; perspective-origin: 0px 0px; \"\u003e\u003cspan style=\"\"\u003e \u003c/span\u003e\u003c/span\u003e\u003ca target='_blank' href = \"https://www.mathworks.com/matlabcentral/cody/problems/813-multiply-2-numbers/solutions/new\"\u003e\u003cspan style=\"\"\u003e\u003cspan style=\"\"\u003e813\u003c/span\u003e\u003c/span\u003e\u003c/a\u003e\u003cspan style=\"display: inline; margin-bottom: 0px; margin-left: 0px; margin-right: 0px; margin-top: 0px; transform-origin: 0px 0px; perspective-origin: 0px 0px; \"\u003e\u003cspan style=\"\"\u003e for help with test suite.\u003c/span\u003e\u003c/span\u003e\u003c/div\u003e\u003c/div\u003e\u003c/div\u003e","function_template":"function y = your_fcn_name(x)\r\n  y = x;\r\nend","test_suite":"%%\r\nx = 1;\r\ny_correct = -1;\r\nassert(isequal(your_fcn_name(x),y_correct))\r\nfiletext = fileread('your_fcn_name.m');\r\nassert(isempty(strfind(filetext, '*')),'sign * forbidden')\r\nassert(isempty(strfind(filetext, 'mtimes')),'mtimes forbidden')\r\nassert(isempty(strfind(filetext, 'cross')),'cross forbidden')\r\nassert(isempty(strfind(filetext, 'prod')),'prod forbidden')\r\nassert(isempty(strfind(filetext, 'cumprod')),'cumprod forbidden')\r\nassert(isempty(strfind(filetext, 'times')),'times forbidden')\r\nassert(isempty(strfind(filetext, 'mldivide')),'mldivide forbidden')\r\nassert(isempty(strfind(filetext, 'mrdivide')),'mrdivide forbidden')\r\nassert(isempty(strfind(filetext, '/')),'/ forbidden')\r\nassert(isempty(strfind(filetext, '\\')),'\\ forbidden')\r\nassert(isempty(strfind(filetext, '-')),'- forbidden')\r\n%assert(isempty(strfind(filetext, '0')),'0 forbidden')\r\nassert(isempty(strfind(filetext, '^')),'^ forbidden')\r\nassert(isempty(strfind(filetext, 'dot')),'dot forbidden')\r\nassert(isempty(strfind(filetext, '''')),'string forbidden')\r\n\r\n%%\r\nx = 8;\r\ny_correct = -8;\r\nassert(isequal(your_fcn_name(x),y_correct))\r\n\r\n%%\r\nx = 8;\r\ny_correct = -8;\r\nassert(isequal(your_fcn_name(x),y_correct))\r\n\r\n%%\r\nx = -148;\r\ny_correct = 148;\r\nassert(isequal(your_fcn_name(x),y_correct))\r\n\r\n%%\r\nx = randi([1 58]);\r\ny_correct = -x;\r\nassert(isequal(your_fcn_name(x),y_correct))\r\n\r\n%%\r\nx = -pi;\r\ny_correct = pi;\r\nassert(isequal(your_fcn_name(x),y_correct))","published":true,"deleted":false,"likes_count":1,"comments_count":4,"created_by":93456,"edited_by":null,"edited_at":null,"deleted_by":null,"deleted_at":null,"solvers_count":71,"test_suite_updated_at":"2020-10-08T13:15:19.000Z","rescore_all_solutions":true,"group_id":1,"created_at":"2016-12-06T23:54:31.000Z","updated_at":"2026-04-03T02:55:07.000Z","published_at":"2016-12-06T23:54:30.000Z","restored_at":null,"restored_by":null,"spam":false,"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\u003eSimple: return a negative number without using the '-' sign.\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\u003eThanks to Problem\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=\\\"https://www.mathworks.com/matlabcentral/cody/problems/813-multiply-2-numbers/solutions/new\\\"\u003e\u003cw:r\u003e\u003cw:t\u003e813\u003c/w:t\u003e\u003c/w:r\u003e\u003c/w:hyperlink\u003e\u003cw:r\u003e\u003cw:t\u003e for help with test suite.\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":42307,"title":"Long-digit Subtraction","description":"Suppose you need to subtract a very large integer from another integer. \u003chttp://www.mathworks.com/matlabcentral/cody/problems/563-how-to-add This problem\u003e requires the player to add two long digits, both supplied as strings, and to return the sum as a string. This problem similarly provides two numbers as strings and you must return the difference as a string (a - b = c). The result will always be positive as a will be larger than b. See the test suite for examples.\r\n","description_html":"\u003cp\u003eSuppose you need to subtract a very large integer from another integer. \u003ca href = \"http://www.mathworks.com/matlabcentral/cody/problems/563-how-to-add\"\u003eThis problem\u003c/a\u003e requires the player to add two long digits, both supplied as strings, and to return the sum as a string. This problem similarly provides two numbers as strings and you must return the difference as a string (a - b = c). The result will always be positive as a will be larger than b. See the test suite for examples.\u003c/p\u003e","function_template":"function c = long_digit_subtraction(a,b)\r\n\r\nc = a - b;\r\n\r\nend\r\n","test_suite":"%%\r\na = '99999';\r\nb = '87654';\r\n%----------\r\nc = '12345';\r\nassert(strcmp(long_digit_subtraction(a,b),c))\r\n\r\n%%\r\na = '99999';\r\nb =  '1234';\r\n%----------\r\nc = '98765';\r\nassert(strcmp(long_digit_subtraction(a,b),c))\r\n\r\n%%\r\na = '99999';\r\nb = '98765';\r\n%----------\r\nc =  '1234';\r\nassert(strcmp(long_digit_subtraction(a,b),c))\r\n\r\n%%\r\na = '99999';\r\nb = '90909';\r\n%----------\r\nc =  '9090';\r\nassert(strcmp(long_digit_subtraction(a,b),c))\r\n\r\n%%\r\na = '11111';\r\nb =  '1234';\r\n%----------\r\nc =  '9877';\r\nassert(strcmp(long_digit_subtraction(a,b),c))\r\n\r\n%%\r\na = '10000';\r\nb =     '1';\r\n%----------\r\nc =  '9999';\r\nassert(strcmp(long_digit_subtraction(a,b),c))\r\n\r\n%%\r\na = '10000000';\r\nb =  '9999999';\r\n%-------------\r\nc =        '1';\r\nassert(strcmp(long_digit_subtraction(a,b),c))\r\n\r\n%%\r\na = '100000000000000000000000000000000000000000000000000000000000000000000';\r\nb =                                                                     '1';\r\n%--------------------------------------------------------------------------\r\nc =  '99999999999999999999999999999999999999999999999999999999999999999999';\r\nassert(strcmp(long_digit_subtraction(a,b),c))\r\n\r\n%%\r\na = '2135476542136876516521651162516';\r\nb =  '165267982494266414654661818517';\r\n%------------------------------------\r\nc = '1970208559642610101866989343999';\r\nassert(strcmp(long_digit_subtraction(a,b),c))\r\n\r\n%%\r\na = '1000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000';\r\nb =                                                                                                                                                             '1';\r\n%------------------------------------------------------------------------------------------------------------------------------------------------------------------\r\nc =  '999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999';\r\nassert(strcmp(long_digit_subtraction(a,b),c))\r\n\r\n%%\r\na = '1000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000';\r\nb =                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                             '1';\r\n%------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------\r\nc =  '999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999';\r\nassert(strcmp(long_digit_subtraction(a,b),c))\r\n\r\n%%\r\nswitch randi(4)\r\n\tcase 1\r\n\t\ta = '99999';\r\n\t\tb = '87654';\r\n\t\tc = '12345';\r\n\tcase 2\r\n\t\ta = '99999';\r\n\t\tb =  '1234';\r\n\t\tc = '98765';\r\n\tcase 3\r\n\t\ta = '10000000';\r\n\t\tb =  '9999999';\r\n\t\tc =        '1';\r\n\tcase 4\r\n\t\ta = '99999';\r\n\t\tb = '90909';\r\n\t\tc =  '9090';\r\nend\r\nassert(strcmp(long_digit_subtraction(a,b),c))\r\n\r\n%%\r\nswitch randi(4)\r\n\tcase 1\r\n\t\ta = '99999';\r\n\t\tb = '98765';\r\n\t\tc =  '1234';\r\n\tcase 2\r\n\t\ta = '10000';\r\n\t\tb =     '1';\r\n\t\tc =  '9999';\r\n\tcase 3\r\n\t\ta = '99999';\r\n\t\tb = '87654';\r\n\t\tc = '12345';\r\n\tcase 4\r\n\t\ta = '2135476542136876516521651162516';\r\n\t\tb =  '165267982494266414654661818517';\r\n\t\tc = '1970208559642610101866989343999';\r\nend\r\nassert(strcmp(long_digit_subtraction(a,b),c))\r\n\r\n%%\r\nswitch randi(4)\r\n\tcase 1\r\n\t\ta = '11111';\r\n\t\tb =  '1234';\r\n\t\tc =  '9877';\r\n\tcase 2\r\n\t\ta = '10000000';\r\n\t\tb =  '9999999';\r\n\t\tc =        '1';\r\n\tcase 3\r\n\t\ta = '99999';\r\n\t\tb = '98765';\r\n\t\tc =  '1234';\r\n\tcase 4\r\n\t\ta = '99999';\r\n\t\tb = '87654';\r\n\t\tc = '12345';\r\nend\r\nassert(strcmp(long_digit_subtraction(a,b),c))\r\n","published":true,"deleted":false,"likes_count":0,"comments_count":0,"created_by":26769,"edited_by":null,"edited_at":null,"deleted_by":null,"deleted_at":null,"solvers_count":24,"test_suite_updated_at":null,"rescore_all_solutions":false,"group_id":1,"created_at":"2015-05-13T01:27:00.000Z","updated_at":"2025-11-03T11:24:33.000Z","published_at":"2015-05-13T01:27:00.000Z","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\u003eSuppose you need to subtract a very large integer from another integer.\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=\\\"http://www.mathworks.com/matlabcentral/cody/problems/563-how-to-add\\\"\u003e\u003cw:r\u003e\u003cw:t\u003eThis problem\u003c/w:t\u003e\u003c/w:r\u003e\u003c/w:hyperlink\u003e\u003cw:r\u003e\u003cw:t\u003e requires the player to add two long digits, both supplied as strings, and to return the sum as a string. This problem similarly provides two numbers as strings and you must return the difference as a string (a - b = c). The result will always be positive as a will be larger than b. See the test suite for examples.\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\"}]}"},{"id":963,"title":"We love vectorized solutions.  Problem 1 : remove the row average.","description":"Given a 2-d matrix, remove the row average from each row.  Your solution MUST be vectorized.  The solution will be tested for accuracy AND speed.  Any for loops will make the solution too slow to pass the speed test.\r\n\r\nExample:\r\n\r\n  a = [ 1 2 ; 3 5 ];\r\n  b = remove_average_vectorized(a);\r\n  % b is [ -0.5 0.5 ; -1 1 ];\r\n","description_html":"\u003cp\u003eGiven a 2-d matrix, remove the row average from each row.  Your solution MUST be vectorized.  The solution will be tested for accuracy AND speed.  Any for loops will make the solution too slow to pass the speed test.\u003c/p\u003e\u003cp\u003eExample:\u003c/p\u003e\u003cpre class=\"language-matlab\"\u003ea = [ 1 2 ; 3 5 ];\r\nb = remove_average_vectorized(a);\r\n% b is [ -0.5 0.5 ; -1 1 ];\r\n\u003c/pre\u003e","function_template":"function y = remove_average_vectorized(x)\r\n    % This works but is too slow.\r\n\r\n    for row=1:size(x,1)\r\n      row_average=mean(x(row,:));\r\n      for col=1:size(x,2)\r\n        x(row,col)=x(row,col)-row_average; \r\n      end\r\n    end\r\n  y=x;\r\nend","test_suite":"x = [ 0 1 ; 2 3 ] ;\r\ny_correct = [ -0.5 0.5 ; -0.5 0.5 ] ;\r\ny = remove_average_vectorized(x);\r\nassert(isequal(y,y_correct));\r\n\r\n%% \r\nx = [ 0 1 ; 2 3 ] ;\r\ntimer=tic;\r\ny = remove_average_vectorized(x);\r\nduration=toc(timer)\r\n% You can probably pass this test with a for loop.\r\nassert(duration\u003c0.1,sprintf('Time used %2.3f\\n',duration)); \r\n\r\n%%\r\nx = [ 1:9999 ; 2:10000 ; [ zeros(1,9998) 9999 ]  ];\r\nx = repmat(x,1000,1);\r\ny_correct = [ -4999:1:4999 ; -4999:1:4999 ; [ repmat(-1,1,9998) 9998 ] ];\r\ny_correct = repmat(y_correct,1000,1);\r\ny = remove_average_vectorized(x);\r\nassert(isequal(y,y_correct));\r\n\r\n%%\r\nx = [ 1:9999 ; 2:10000 ; [ zeros(1,9998) 9999 ]  ];\r\nx = repmat(x,1000,1);\r\ntimer=tic;\r\ny = remove_average_vectorized(x);\r\nduration=toc(timer)\r\n% A decent vectorized solution should take around 1 second.\r\nassert(duration\u003c2,sprintf('Time used %2.3f\\n',duration)); ","published":true,"deleted":false,"likes_count":7,"comments_count":12,"created_by":6808,"edited_by":null,"edited_at":null,"deleted_by":null,"deleted_at":null,"solvers_count":884,"test_suite_updated_at":"2012-10-02T05:21:12.000Z","rescore_all_solutions":false,"group_id":12,"created_at":"2012-10-01T06:43:20.000Z","updated_at":"2026-01-19T06:40:50.000Z","published_at":"2012-10-01T07:30:28.000Z","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\u003eGiven a 2-d matrix, remove the row average from each row. Your solution MUST be vectorized. The solution will be tested for accuracy AND speed. Any for loops will make the solution too slow to pass the speed test.\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\u003eExample:\u003c/w:t\u003e\u003c/w:r\u003e\u003c/w:p\u003e\u003cw:p\u003e\u003cw:pPr\u003e\u003cw:pStyle w:val=\\\"code\\\"/\u003e\u003c/w:pPr\u003e\u003cw:r\u003e\u003cw:t\u003e\u003c![CDATA[a = [ 1 2 ; 3 5 ];\\nb = remove_average_vectorized(a);\\n% b is [ -0.5 0.5 ; -1 1 ];]]\u003e\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\"}]}"},{"id":43738,"title":"Negative without '-'","description":"Simple: return a negative number without using the '-' sign.\r\n\r\nThanks to Problem \u003chttps://www.mathworks.com/matlabcentral/cody/problems/813-multiply-2-numbers/solutions/new 813\u003e for help with test suite.","description_html":"\u003cdiv style = \"text-align: start; line-height: 20px; 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: normal; text-decoration: none; white-space: normal; \"\u003e\u003cdiv style=\"display: block; min-width: 0px; padding-top: 0px; transform-origin: 332px 25.5px; vertical-align: baseline; perspective-origin: 332px 25.5px; \"\u003e\u003cdiv style=\"font-family: Helvetica, Arial, sans-serif; line-height: 21px; margin-bottom: 9px; margin-left: 4px; margin-right: 10px; margin-top: 2px; text-align: left; transform-origin: 309px 10.5px; white-space: pre-wrap; perspective-origin: 309px 10.5px; margin-left: 4px; margin-top: 2px; margin-bottom: 9px; margin-right: 10px; \"\u003e\u003cspan style=\"display: inline; margin-bottom: 0px; margin-left: 0px; margin-right: 0px; margin-top: 0px; transform-origin: 0px 0px; perspective-origin: 0px 0px; \"\u003e\u003cspan style=\"\"\u003eSimple: return a negative number without using the '-' sign.\u003c/span\u003e\u003c/span\u003e\u003c/div\u003e\u003cdiv style=\"font-family: Helvetica, Arial, sans-serif; line-height: 21px; margin-bottom: 9px; margin-left: 4px; margin-right: 10px; margin-top: 2px; text-align: left; transform-origin: 309px 10.5px; white-space: pre-wrap; perspective-origin: 309px 10.5px; margin-left: 4px; margin-top: 2px; margin-bottom: 9px; margin-right: 10px; \"\u003e\u003cspan style=\"display: inline; margin-bottom: 0px; margin-left: 0px; margin-right: 0px; margin-top: 0px; transform-origin: 0px 0px; perspective-origin: 0px 0px; \"\u003e\u003cspan style=\"\"\u003eThanks to Problem\u003c/span\u003e\u003c/span\u003e\u003cspan style=\"display: inline; margin-bottom: 0px; margin-left: 0px; margin-right: 0px; margin-top: 0px; transform-origin: 0px 0px; perspective-origin: 0px 0px; \"\u003e\u003cspan style=\"\"\u003e \u003c/span\u003e\u003c/span\u003e\u003ca target='_blank' href = \"https://www.mathworks.com/matlabcentral/cody/problems/813-multiply-2-numbers/solutions/new\"\u003e\u003cspan style=\"\"\u003e\u003cspan style=\"\"\u003e813\u003c/span\u003e\u003c/span\u003e\u003c/a\u003e\u003cspan style=\"display: inline; margin-bottom: 0px; margin-left: 0px; margin-right: 0px; margin-top: 0px; transform-origin: 0px 0px; perspective-origin: 0px 0px; \"\u003e\u003cspan style=\"\"\u003e for help with test suite.\u003c/span\u003e\u003c/span\u003e\u003c/div\u003e\u003c/div\u003e\u003c/div\u003e","function_template":"function y = your_fcn_name(x)\r\n  y = x;\r\nend","test_suite":"%%\r\nx = 1;\r\ny_correct = -1;\r\nassert(isequal(your_fcn_name(x),y_correct))\r\nfiletext = fileread('your_fcn_name.m');\r\nassert(isempty(strfind(filetext, '*')),'sign * forbidden')\r\nassert(isempty(strfind(filetext, 'mtimes')),'mtimes forbidden')\r\nassert(isempty(strfind(filetext, 'cross')),'cross forbidden')\r\nassert(isempty(strfind(filetext, 'prod')),'prod forbidden')\r\nassert(isempty(strfind(filetext, 'cumprod')),'cumprod forbidden')\r\nassert(isempty(strfind(filetext, 'times')),'times forbidden')\r\nassert(isempty(strfind(filetext, 'mldivide')),'mldivide forbidden')\r\nassert(isempty(strfind(filetext, 'mrdivide')),'mrdivide forbidden')\r\nassert(isempty(strfind(filetext, '/')),'/ forbidden')\r\nassert(isempty(strfind(filetext, '\\')),'\\ forbidden')\r\nassert(isempty(strfind(filetext, '-')),'- forbidden')\r\n%assert(isempty(strfind(filetext, '0')),'0 forbidden')\r\nassert(isempty(strfind(filetext, '^')),'^ forbidden')\r\nassert(isempty(strfind(filetext, 'dot')),'dot forbidden')\r\nassert(isempty(strfind(filetext, '''')),'string forbidden')\r\n\r\n%%\r\nx = 8;\r\ny_correct = -8;\r\nassert(isequal(your_fcn_name(x),y_correct))\r\n\r\n%%\r\nx = 8;\r\ny_correct = -8;\r\nassert(isequal(your_fcn_name(x),y_correct))\r\n\r\n%%\r\nx = -148;\r\ny_correct = 148;\r\nassert(isequal(your_fcn_name(x),y_correct))\r\n\r\n%%\r\nx = randi([1 58]);\r\ny_correct = -x;\r\nassert(isequal(your_fcn_name(x),y_correct))\r\n\r\n%%\r\nx = -pi;\r\ny_correct = pi;\r\nassert(isequal(your_fcn_name(x),y_correct))","published":true,"deleted":false,"likes_count":1,"comments_count":4,"created_by":93456,"edited_by":null,"edited_at":null,"deleted_by":null,"deleted_at":null,"solvers_count":71,"test_suite_updated_at":"2020-10-08T13:15:19.000Z","rescore_all_solutions":true,"group_id":1,"created_at":"2016-12-06T23:54:31.000Z","updated_at":"2026-04-03T02:55:07.000Z","published_at":"2016-12-06T23:54:30.000Z","restored_at":null,"restored_by":null,"spam":false,"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 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suite.\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:\"subtraction\"","current_player_id":null,"fields":[{"name":"page","type":"integer","callback":null,"default":1,"directive":null,"facet":null,"facet_method":"and","operator":null,"param":null,"static":null,"prepend":true},{"name":"per_page","type":"integer","callback":null,"default":50,"directive":null,"facet":null,"facet_method":"and","operator":null,"param":null,"static":null,"prepend":true},{"name":"sort","type":"string","callback":null,"default":null,"directive":null,"facet":null,"facet_method":"and","operator":null,"param":null,"static":null,"prepend":true},{"name":"body","type":"text","callback":null,"default":"*:*","directive":null,"facet":null,"facet_method":"and","operator":null,"param":"term","static":null,"prepend":false},{"name":"group","type":"string","callback":null,"default":null,"directive":"group","facet":true,"facet_method":"and","operator":null,"param":"term","static":null,"prepend":true},{"name":"difficulty_rating_bin","type":"string","callback":null,"default":null,"directive":"difficulty_rating_bin","facet":true,"facet_method":"and","operator":null,"param":"term","static":null,"prepend":true},{"name":"id","type":"integer","callback":null,"default":null,"directive":"id","facet":null,"facet_method":"and","operator":null,"param":"term","static":null,"prepend":true},{"name":"tag","type":"string","callback":null,"default":null,"directive":"tag","facet":null,"facet_method":"and","operator":null,"param":"term","static":null,"prepend":true},{"name":"product","type":"string","callback":null,"default":null,"directive":"product","facet":null,"facet_method":"and","operator":null,"param":"term","static":null,"prepend":true},{"name":"created_at","type":"timeframe","callback":{},"default":null,"directive":"created_at","facet":null,"facet_method":"and","operator":null,"param":"term","static":null,"prepend":true},{"name":"profile_id","type":"integer","callback":null,"default":null,"directive":"author_id","facet":null,"facet_method":"and","operator":null,"param":"term","static":null,"prepend":true},{"name":"created_by","type":"string","callback":null,"default":null,"directive":"author","facet":null,"facet_method":"and","operator":null,"param":"term","static":null,"prepend":true},{"name":"player_id","type":"integer","callback":null,"default":null,"directive":"solver_id","facet":null,"facet_method":"and","operator":null,"param":"term","static":null,"prepend":true},{"name":"player","type":"string","callback":null,"default":null,"directive":"solver","facet":null,"facet_method":"and","operator":null,"param":"term","static":null,"prepend":true},{"name":"solvers_count","type":"integer","callback":null,"default":null,"directive":"solvers_count","facet":null,"facet_method":"and","operator":null,"param":"term","static":null,"prepend":true},{"name":"comments_count","type":"integer","callback":null,"default":null,"directive":"comments_count","facet":null,"facet_method":"and","operator":null,"param":"term","static":null,"prepend":true},{"name":"likes_count","type":"integer","callback":null,"default":null,"directive":"likes_count","facet":null,"facet_method":"and","operator":null,"param":"term","static":null,"prepend":true},{"name":"leader_id","type":"integer","callback":null,"default":null,"directive":"leader_id","facet":null,"facet_method":"and","operator":null,"param":"term","static":null,"prepend":true},{"name":"leading_solution","type":"integer","callback":null,"default":null,"directive":"leading_solution","facet":null,"facet_method":"and","operator":null,"param":"term","static":null,"prepend":true}],"filters":[{"name":"asset_type","type":"string","callback":null,"default":null,"directive":null,"facet":null,"facet_method":"and","operator":null,"param":null,"static":"\"cody:problem\"","prepend":true},{"name":"profile_id","type":"integer","callback":{},"default":null,"directive":null,"facet":null,"facet_method":"and","operator":null,"param":"author_id","static":null,"prepend":true}],"query":{"params":{"per_page":50,"term":"tag:\"subtraction\"","current_player":null,"sort":"map(difficulty_value,0,0,999) 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