{"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":2313,"title":"Narcissistic problem","description":"How many likes has this problem?","description_html":"\u003cp\u003eHow many likes has this problem?\u003c/p\u003e","function_template":"function y = like_me(x)\r\n  y = x;\r\nend","test_suite":"%%\r\n% this problem will be updated,\r\n% your score/size can change over time\r\n% if you submit a fixed value :-)\r\n%%\r\ny=like_me();\r\nassert(isequal(mod(y,1),0));\r\n%%\r\ny=like_me();\r\nassert(y\u003e0);\r\n%%\r\ny=like_me();\r\nurl='http://www.mathworks.co.uk/matlabcentral/cody/problems/2313'\r\n% the main problem with this problem is that ...\r\n% this problem thinks.\r\n% it thinks about itself most of the time.\r\n% it is convinced, that at least X likes has it.\r\ny_sub_correct=max([10 cellfun(@(S)str2num(cell2mat(S)),regexp(urlread(url),'(\\d*) players\u003c/a\u003e like this problem','tokens'))]); % probably hackable by comments?\r\nt = mtree('like_me.m','-file');\r\nsize = length(t.nodesize);\r\n% this problem likes compliments,\r\n% even false.\r\n% For good compliment it is going to pass your solution with a smaller size! \r\n% But if you don't appreciate it, it can punish you...\r\nfeval(@assignin,'caller','score',round(max(0,size*(.5+.5*y_sub_correct/y))));\r\n","published":true,"deleted":false,"likes_count":30,"comments_count":4,"created_by":14358,"edited_by":null,"edited_at":null,"deleted_by":null,"deleted_at":null,"solvers_count":166,"test_suite_updated_at":"2014-12-05T16:31:19.000Z","rescore_all_solutions":true,"group_id":1,"created_at":"2014-05-08T09:18:27.000Z","updated_at":"2026-02-14T16:20:13.000Z","published_at":"2014-05-08T09:25:53.000Z","restored_at":null,"restored_by":null,"spam":false,"simulink":false,"admin_reviewed":false,"description_opc":"{\"relationships\":[{\"relationshipType\":\"http://schemas.mathworks.com/matlab/code/2013/relationships/document\",\"relationshipId\":\"rId1\",\"target\":\"/matlab/document.xml\"},{\"relationshipType\":\"http://schemas.mathworks.com/matlab/code/2013/relationships/output\",\"relationshipId\":\"rId2\",\"target\":\"/matlab/output.xml\"}],\"parts\":[{\"partUri\":\"/matlab/document.xml\",\"relationship\":[],\"contentType\":\"application/vnd.mathworks.matlab.code.document+xml\",\"content\":\"\u003c?xml version=\\\"1.0\\\" encoding=\\\"UTF-8\\\"?\u003e\u003cw:document xmlns:w=\\\"http://schemas.openxmlformats.org/wordprocessingml/2006/main\\\"\u003e\u003cw:body\u003e\u003cw:p\u003e\u003cw:pPr\u003e\u003cw:pStyle w:val=\\\"text\\\"/\u003e\u003c/w:pPr\u003e\u003cw:r\u003e\u003cw:t\u003eHow many likes has this problem?\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":2312,"title":"How many solutions has this problem?","description":"Guess, predict or calculate :-)\r\n\r\n(You will be scored by the accuracy).\r\n\r\n\r\n\r\n\r\nUpdate: \u003chttp://www.mathworks.co.uk/matlabcentral/about/trendy/ TRENDY\u003e \u003chttp://www.mathworks.co.uk/matlabcentral/trendy/Tutorial/urlfilter.html is\u003e here!","description_html":"\u003cp\u003eGuess, predict or calculate :-)\u003c/p\u003e\u003cp\u003e(You will be scored by the accuracy).\u003c/p\u003e\u003cp\u003eUpdate: \u003ca href = \"http://www.mathworks.co.uk/matlabcentral/about/trendy/\"\u003eTRENDY\u003c/a\u003e \u003ca href = \"http://www.mathworks.co.uk/matlabcentral/trendy/Tutorial/urlfilter.html\"\u003eis\u003c/a\u003e here!\u003c/p\u003e","function_template":"function y = solutions(x)\r\n  y = 42;\r\nend","test_suite":"%%\r\n% please ''ignore'' this first test, this code is here to put function \r\n% urlfilter known from matlabcentral/trendy to the path for this problem\r\n% (method taken from Doug's Hull problem Steal, Share, or Catch)\r\nfh=fopen('urlfilter.m','wt');\r\nfprintf(fh, '%s \\n', 'function out = urlfilter(url, target, numNumbers, direction)') ;\r\nfprintf(fh, '%s \\n', '  if nargin \u003c 3, numNumbers = 1; end');\r\nfprintf(fh, '%s \\n', '  if nargin \u003c 4 direction = ''forward''; end');\r\nfprintf(fh, '%s \\n', '  % If url is not an actual URL, then treat it as a string');\r\nfprintf(fh, '%s \\n', '  if strcmp(url(1:4),''http''), textStr = urlread(url); else textStr = url; end');\r\nfprintf(fh, '%s \\n', '  % Handle special case where two numbers are given as part of a range');\r\nfprintf(fh, '%s \\n', '  %   Example: \"annual rainfall = 20-40 inches\"');\r\nfprintf(fh, '%s \\n', '  % Solution is a pre-processing step that replaces the dash with a space');\r\nfprintf(fh, '%s \\n', '  %   Example: \"annual rainfall = 20 40 inches\"');\r\nfprintf(fh, '%s \\n', '  textStr = regexprep(textStr,''(\\d+)-(\\d+)'',''$1 $2'');');\r\nfprintf(fh, '%s \\n', '  strIndex = strfind(textStr,target);');\r\nfprintf(fh, '%s \\n', '  if isempty(strIndex),');\r\nfprintf(fh, '%s \\n', '    error( ''trendy:urlfilter:TargetStringNotFound'', ...');\r\nfprintf(fh, '%s \\n', '          [''Target string '' target '' does not appear''])');\r\nfprintf(fh, '%s \\n', '  end');\r\nfprintf(fh, '%s \\n', '  % Start looking after the first appearance of the target');\r\nfprintf(fh, '%s \\n', '  if strcmp(direction,''forward'')');\r\nfprintf(fh, '%s \\n', '    strIndex = strIndex(1) + length(target);');\r\nfprintf(fh, '%s \\n', '  elseif strcmp(direction,''backward'')');\r\nfprintf(fh, '%s \\n', '    strIndex = strIndex(1) - 1;');\r\nfprintf(fh, '%s \\n', '  else');\r\nfprintf(fh, '%s \\n', '    error( ''trendy:urlfilter:InvalidDirectionFlag'', ...');\r\nfprintf(fh, '%s \\n', '           ''DIRECTION must be either ''''forward'''' or ''''backward''''.'' );');\r\nfprintf(fh, '%s \\n', '  end');\r\nfprintf(fh, '%s \\n', '  out = zeros(1,numNumbers);');\r\nfprintf(fh, '%s \\n', '  for i = 1:numNumbers');\r\nfprintf(fh, '%s \\n', '    [out(i),strIndex] = getNextNumber(textStr,strIndex,direction);');\r\nfprintf(fh, '%s \\n', '  end');\r\nfprintf(fh, '%s \\n', 'end');\r\nfprintf(fh, '%s \\n', '% =========================');\r\nfprintf(fh, '%s \\n', 'function [nextNumber,strIndex] = getNextNumber(textStr,strIndex,direction)');\r\nfprintf(fh, '%s \\n', '  % Use a state machine to sift through the HTML for numbers.');\r\nfprintf(fh, '%s \\n', '  if strcmp(direction,''forward'')');\r\nfprintf(fh, '%s \\n', '    openTagSymbol  = ''\u003c'';');\r\nfprintf(fh, '%s \\n', '    closeTagSymbol = ''\u003e'';');\r\nfprintf(fh, '%s \\n', '    moveIndexFcn   = @(x) x+1;');\r\nfprintf(fh, '%s \\n', '    concatenateFcn = @(a,b) [a b];');\r\nfprintf(fh, '%s \\n', '  else');\r\nfprintf(fh, '%s \\n', '    openTagSymbol  = ''\u003e'';');\r\nfprintf(fh, '%s \\n', '    closeTagSymbol = ''\u003c'';');\r\nfprintf(fh, '%s \\n', '    moveIndexFcn   = @(x) x-1;');\r\nfprintf(fh, '%s \\n', '    concatenateFcn = @(a,b) [b a];');\r\nfprintf(fh, '%s \\n', '  end');\r\nfprintf(fh, '%s \\n', '  urlStrLen = length(textStr);');\r\nfprintf(fh, '%s \\n', '  state = ''notnumber'';');\r\nfprintf(fh, '%s \\n', '  while true');\r\nfprintf(fh, '%s \\n', '    ch = textStr(strIndex);');\r\nfprintf(fh, '%s \\n', '    switch state');\r\nfprintf(fh, '%s \\n', '      case ''notnumber''');\r\nfprintf(fh, '%s \\n', '        if isDigitDotDashOrComma(ch)');\r\nfprintf(fh, '%s \\n', '          state = ''number'';');\r\nfprintf(fh, '%s \\n', '          numStr = ch;');\r\nfprintf(fh, '%s \\n', '        elseif (ch == openTagSymbol)');\r\nfprintf(fh, '%s \\n', '          state = ''tagbody'';');\r\nfprintf(fh, '%s \\n', '        end');\r\nfprintf(fh, '%s \\n', '      case ''tagbody''');\r\nfprintf(fh, '%s \\n', '        % Throw away anything inside the tag markup area');\r\nfprintf(fh, '%s \\n', '        if (ch == closeTagSymbol)');\r\nfprintf(fh, '%s \\n', '          state = ''notnumber'';');\r\nfprintf(fh, '%s \\n', '        end ');\r\nfprintf(fh, '%s \\n', '      case ''number''');\r\nfprintf(fh, '%s \\n', '        if isDigitDotDashOrComma(ch)');\r\nfprintf(fh, '%s \\n', '          numStr = concatenateFcn(numStr,ch);');\r\nfprintf(fh, '%s \\n', '        else');\r\nfprintf(fh, '%s \\n', '          % We are transitioning out of a number.');\r\nfprintf(fh, '%s \\n', '          % Note that STR2DOUBLE handles commas in the string.');\r\nfprintf(fh, '%s \\n', '          nextNumber = str2double(numStr);');\r\nfprintf(fh, '%s \\n', '          if ~isnan(nextNumber)');\r\nfprintf(fh, '%s \\n', '            % The number is valid. We''re all done.');\r\nfprintf(fh, '%s \\n', '            break');\r\nfprintf(fh, '%s \\n', '          else');\r\nfprintf(fh, '%s \\n', '            % The number is bogus. Throw it away and continue.');\r\nfprintf(fh, '%s \\n', '            if (ch == openTagSymbol), state = ''tagbody''; else state = ''notnumber''; end');\r\nfprintf(fh, '%s \\n', '          end');\r\nfprintf(fh, '%s \\n', '        end');\r\nfprintf(fh, '%s \\n', '      otherwise');\r\nfprintf(fh, '%s \\n', '        error( ''trendy:urlfilter:InvalidState'', ...');\r\nfprintf(fh, '%s \\n', '             [''Encountered unknown state '' state])');\r\nfprintf(fh, '%s \\n', '    end');\r\nfprintf(fh, '%s \\n', '    strIndex = moveIndexFcn(strIndex);');\r\nfprintf(fh, '%s \\n', '    if (strIndex == 0) || (strIndex \u003e urlStrLen)');\r\nfprintf(fh, '%s \\n', '      % We ran off the end of the string.');\r\nfprintf(fh, '%s \\n', '      disp(''End of file reached.'')');\r\nfprintf(fh, '%s \\n', '      break');\r\nfprintf(fh, '%s \\n', '    end');\r\nfprintf(fh, '%s \\n', '  end');\r\nfprintf(fh, '%s \\n', 'end');\r\nfprintf(fh, '%s \\n', '% ==================');\r\nfprintf(fh, '%s \\n', 'function tf = isDigitDotDashOrComma(ch)');\r\nfprintf(fh, '%s \\n', '  tf = ((ch \u003e= ''0'') \u0026\u0026 (ch \u003c= ''9'')) || ...');\r\nfprintf(fh, '%s \\n', '          (ch == ''.'') || (ch == ''-'') || (ch == '','');');\r\nfprintf(fh, '%s \\n', 'end');\r\nfclose(fh);\r\n%%\r\nrehash path\r\n%%\r\ny=solutions();\r\nassert(isequal(mod(y,1),0))\r\n%%\r\ny=solutions();\r\nassert(y\u003e0);\r\n%%\r\ny=solutions();\r\n% yes, yes solution hidden in the test suite... try to code adifferent one! :-)\r\nurl='http://www.mathworks.co.uk/matlabcentral/cody/problems/2312'\r\ny_correct=max([0 cellfun(@(S)str2num(cell2mat(S)),regexp(urlread(url),'\u003cspan class=\"solution_statistic\"\u003e(\\d*)\u003c/span\u003e\u003cspan class=\"text\"\u003e Solutions\u003c/span\u003e','tokens'))]) + 1; % don't forget your solution\r\nt = mtree('solutions.m','-file');\r\nsize = ceil(length(t.nodesize)/13);\r\nfeval(@assignin,'caller','score',abs(y-y_correct)+size);\r\n% (... and solutions will be rescored from time to time :-D)\r\n","published":true,"deleted":false,"likes_count":2,"comments_count":1,"created_by":14358,"edited_by":null,"edited_at":null,"deleted_by":null,"deleted_at":null,"solvers_count":68,"test_suite_updated_at":"2014-05-12T12:02:31.000Z","rescore_all_solutions":false,"group_id":1,"created_at":"2014-05-08T08:33:51.000Z","updated_at":"2026-02-18T14:23:20.000Z","published_at":"2014-05-08T09:06:48.000Z","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\u003eGuess, predict or calculate :-)\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\u003e(You will be scored by the accuracy).\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\u003eUpdate:\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.co.uk/matlabcentral/about/trendy/\\\"\u003e\u003cw:r\u003e\u003cw:t\u003eTRENDY\u003c/w:t\u003e\u003c/w:r\u003e\u003c/w:hyperlink\u003e\u003cw:r\u003e\u003cw:t\u003e \u003c/w:t\u003e\u003c/w:r\u003e\u003cw:hyperlink w:docLocation=\\\"http://www.mathworks.co.uk/matlabcentral/trendy/Tutorial/urlfilter.html\\\"\u003e\u003cw:r\u003e\u003cw:t\u003eis\u003c/w:t\u003e\u003c/w:r\u003e\u003c/w:hyperlink\u003e\u003cw:r\u003e\u003cw:t\u003e here!\u003c/w:t\u003e\u003c/w:r\u003e\u003c/w:p\u003e\u003c/w:body\u003e\u003c/w:document\u003e\"},{\"partUri\":\"/matlab/output.xml\",\"contentType\":\"text/xml\",\"content\":\"\u003c?xml version=\\\"1.0\\\" encoding=\\\"UTF-8\\\" standalone=\\\"no\\\" ?\u003e\u003cembeddedOutputs\u003e\u003cmetaData\u003e\u003cevaluationState\u003emanual\u003c/evaluationState\u003e\u003clayoutState\u003ecode\u003c/layoutState\u003e\u003coutputStatus\u003eready\u003c/outputStatus\u003e\u003c/metaData\u003e\u003coutputArray type=\\\"array\\\"/\u003e\u003cregionArray type=\\\"array\\\"/\u003e\u003c/embeddedOutputs\u003e\"}]}"}],"problem_search":{"errors":[],"problems":[{"id":2313,"title":"Narcissistic problem","description":"How many likes has this problem?","description_html":"\u003cp\u003eHow many likes has this problem?\u003c/p\u003e","function_template":"function y = like_me(x)\r\n  y = x;\r\nend","test_suite":"%%\r\n% this problem will be updated,\r\n% your score/size can change over time\r\n% if you submit a fixed value :-)\r\n%%\r\ny=like_me();\r\nassert(isequal(mod(y,1),0));\r\n%%\r\ny=like_me();\r\nassert(y\u003e0);\r\n%%\r\ny=like_me();\r\nurl='http://www.mathworks.co.uk/matlabcentral/cody/problems/2313'\r\n% the main problem with this problem is that ...\r\n% this problem thinks.\r\n% it thinks about itself most of the time.\r\n% it is convinced, that at least X likes has it.\r\ny_sub_correct=max([10 cellfun(@(S)str2num(cell2mat(S)),regexp(urlread(url),'(\\d*) players\u003c/a\u003e like this problem','tokens'))]); % probably hackable by comments?\r\nt = mtree('like_me.m','-file');\r\nsize = length(t.nodesize);\r\n% this problem likes compliments,\r\n% even false.\r\n% For good compliment it is going to pass your solution with a smaller size! \r\n% But if you don't appreciate it, it can punish you...\r\nfeval(@assignin,'caller','score',round(max(0,size*(.5+.5*y_sub_correct/y))));\r\n","published":true,"deleted":false,"likes_count":30,"comments_count":4,"created_by":14358,"edited_by":null,"edited_at":null,"deleted_by":null,"deleted_at":null,"solvers_count":166,"test_suite_updated_at":"2014-12-05T16:31:19.000Z","rescore_all_solutions":true,"group_id":1,"created_at":"2014-05-08T09:18:27.000Z","updated_at":"2026-02-14T16:20:13.000Z","published_at":"2014-05-08T09:25:53.000Z","restored_at":null,"restored_by":null,"spam":false,"simulink":false,"admin_reviewed":false,"description_opc":"{\"relationships\":[{\"relationshipType\":\"http://schemas.mathworks.com/matlab/code/2013/relationships/document\",\"relationshipId\":\"rId1\",\"target\":\"/matlab/document.xml\"},{\"relationshipType\":\"http://schemas.mathworks.com/matlab/code/2013/relationships/output\",\"relationshipId\":\"rId2\",\"target\":\"/matlab/output.xml\"}],\"parts\":[{\"partUri\":\"/matlab/document.xml\",\"relationship\":[],\"contentType\":\"application/vnd.mathworks.matlab.code.document+xml\",\"content\":\"\u003c?xml version=\\\"1.0\\\" encoding=\\\"UTF-8\\\"?\u003e\u003cw:document xmlns:w=\\\"http://schemas.openxmlformats.org/wordprocessingml/2006/main\\\"\u003e\u003cw:body\u003e\u003cw:p\u003e\u003cw:pPr\u003e\u003cw:pStyle w:val=\\\"text\\\"/\u003e\u003c/w:pPr\u003e\u003cw:r\u003e\u003cw:t\u003eHow many likes has this problem?\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":2312,"title":"How many solutions has this problem?","description":"Guess, predict or calculate :-)\r\n\r\n(You will be scored by the accuracy).\r\n\r\n\r\n\r\n\r\nUpdate: \u003chttp://www.mathworks.co.uk/matlabcentral/about/trendy/ TRENDY\u003e \u003chttp://www.mathworks.co.uk/matlabcentral/trendy/Tutorial/urlfilter.html is\u003e here!","description_html":"\u003cp\u003eGuess, predict or calculate :-)\u003c/p\u003e\u003cp\u003e(You will be scored by the accuracy).\u003c/p\u003e\u003cp\u003eUpdate: \u003ca href = \"http://www.mathworks.co.uk/matlabcentral/about/trendy/\"\u003eTRENDY\u003c/a\u003e \u003ca href = \"http://www.mathworks.co.uk/matlabcentral/trendy/Tutorial/urlfilter.html\"\u003eis\u003c/a\u003e here!\u003c/p\u003e","function_template":"function y = solutions(x)\r\n  y = 42;\r\nend","test_suite":"%%\r\n% please ''ignore'' this first test, this code is here to put function \r\n% urlfilter known from matlabcentral/trendy to the path for this problem\r\n% (method taken from Doug's Hull problem Steal, Share, or Catch)\r\nfh=fopen('urlfilter.m','wt');\r\nfprintf(fh, '%s \\n', 'function out = urlfilter(url, target, numNumbers, direction)') ;\r\nfprintf(fh, '%s \\n', '  if nargin \u003c 3, numNumbers = 1; end');\r\nfprintf(fh, '%s \\n', '  if nargin \u003c 4 direction = ''forward''; end');\r\nfprintf(fh, '%s \\n', '  % If url is not an actual URL, then treat it as a string');\r\nfprintf(fh, '%s \\n', '  if strcmp(url(1:4),''http''), textStr = urlread(url); else textStr = url; end');\r\nfprintf(fh, '%s \\n', '  % Handle special case where two numbers are given as part of a range');\r\nfprintf(fh, '%s \\n', '  %   Example: \"annual rainfall = 20-40 inches\"');\r\nfprintf(fh, '%s \\n', '  % Solution is a pre-processing step that replaces the dash with a space');\r\nfprintf(fh, '%s \\n', '  %   Example: \"annual rainfall = 20 40 inches\"');\r\nfprintf(fh, '%s \\n', '  textStr = regexprep(textStr,''(\\d+)-(\\d+)'',''$1 $2'');');\r\nfprintf(fh, '%s \\n', '  strIndex = strfind(textStr,target);');\r\nfprintf(fh, '%s \\n', '  if isempty(strIndex),');\r\nfprintf(fh, '%s \\n', '    error( ''trendy:urlfilter:TargetStringNotFound'', ...');\r\nfprintf(fh, '%s \\n', '          [''Target string '' target '' does not appear''])');\r\nfprintf(fh, '%s \\n', '  end');\r\nfprintf(fh, '%s \\n', '  % Start looking after the first appearance of the target');\r\nfprintf(fh, '%s \\n', '  if strcmp(direction,''forward'')');\r\nfprintf(fh, '%s \\n', '    strIndex = strIndex(1) + length(target);');\r\nfprintf(fh, '%s \\n', '  elseif strcmp(direction,''backward'')');\r\nfprintf(fh, '%s \\n', '    strIndex = strIndex(1) - 1;');\r\nfprintf(fh, '%s \\n', '  else');\r\nfprintf(fh, '%s \\n', '    error( ''trendy:urlfilter:InvalidDirectionFlag'', ...');\r\nfprintf(fh, '%s \\n', '           ''DIRECTION must be either ''''forward'''' or ''''backward''''.'' );');\r\nfprintf(fh, '%s \\n', '  end');\r\nfprintf(fh, '%s \\n', '  out = zeros(1,numNumbers);');\r\nfprintf(fh, '%s \\n', '  for i = 1:numNumbers');\r\nfprintf(fh, '%s \\n', '    [out(i),strIndex] = getNextNumber(textStr,strIndex,direction);');\r\nfprintf(fh, '%s \\n', '  end');\r\nfprintf(fh, '%s \\n', 'end');\r\nfprintf(fh, '%s \\n', '% =========================');\r\nfprintf(fh, '%s \\n', 'function [nextNumber,strIndex] = getNextNumber(textStr,strIndex,direction)');\r\nfprintf(fh, '%s \\n', '  % Use a state machine to sift through the HTML for numbers.');\r\nfprintf(fh, '%s \\n', '  if strcmp(direction,''forward'')');\r\nfprintf(fh, '%s \\n', '    openTagSymbol  = ''\u003c'';');\r\nfprintf(fh, '%s \\n', '    closeTagSymbol = ''\u003e'';');\r\nfprintf(fh, '%s \\n', '    moveIndexFcn   = @(x) x+1;');\r\nfprintf(fh, '%s \\n', '    concatenateFcn = @(a,b) [a b];');\r\nfprintf(fh, '%s \\n', '  else');\r\nfprintf(fh, '%s \\n', '    openTagSymbol  = ''\u003e'';');\r\nfprintf(fh, '%s \\n', '    closeTagSymbol = ''\u003c'';');\r\nfprintf(fh, '%s \\n', '    moveIndexFcn   = @(x) x-1;');\r\nfprintf(fh, '%s \\n', '    concatenateFcn = @(a,b) [b a];');\r\nfprintf(fh, '%s \\n', '  end');\r\nfprintf(fh, '%s \\n', '  urlStrLen = length(textStr);');\r\nfprintf(fh, '%s \\n', '  state = ''notnumber'';');\r\nfprintf(fh, '%s \\n', '  while true');\r\nfprintf(fh, '%s \\n', '    ch = textStr(strIndex);');\r\nfprintf(fh, '%s \\n', '    switch state');\r\nfprintf(fh, '%s \\n', '      case ''notnumber''');\r\nfprintf(fh, '%s \\n', '        if isDigitDotDashOrComma(ch)');\r\nfprintf(fh, '%s \\n', '          state = ''number'';');\r\nfprintf(fh, '%s \\n', '          numStr = ch;');\r\nfprintf(fh, '%s \\n', '        elseif (ch == openTagSymbol)');\r\nfprintf(fh, '%s \\n', '          state = ''tagbody'';');\r\nfprintf(fh, '%s \\n', '        end');\r\nfprintf(fh, '%s \\n', '      case ''tagbody''');\r\nfprintf(fh, '%s \\n', '        % Throw away anything inside the tag markup area');\r\nfprintf(fh, '%s \\n', '        if (ch == closeTagSymbol)');\r\nfprintf(fh, '%s \\n', '          state = ''notnumber'';');\r\nfprintf(fh, '%s \\n', '        end ');\r\nfprintf(fh, '%s \\n', '      case ''number''');\r\nfprintf(fh, '%s \\n', '        if isDigitDotDashOrComma(ch)');\r\nfprintf(fh, '%s \\n', '          numStr = concatenateFcn(numStr,ch);');\r\nfprintf(fh, '%s \\n', '        else');\r\nfprintf(fh, '%s \\n', '          % We are transitioning out of a number.');\r\nfprintf(fh, '%s \\n', '          % Note that STR2DOUBLE handles commas in the string.');\r\nfprintf(fh, '%s \\n', '          nextNumber = str2double(numStr);');\r\nfprintf(fh, '%s \\n', '          if ~isnan(nextNumber)');\r\nfprintf(fh, '%s \\n', '            % The number is valid. We''re all done.');\r\nfprintf(fh, '%s \\n', '            break');\r\nfprintf(fh, '%s \\n', '          else');\r\nfprintf(fh, '%s \\n', '            % The number is bogus. Throw it away and continue.');\r\nfprintf(fh, '%s \\n', '            if (ch == openTagSymbol), state = ''tagbody''; else state = ''notnumber''; end');\r\nfprintf(fh, '%s \\n', '          end');\r\nfprintf(fh, '%s \\n', '        end');\r\nfprintf(fh, '%s \\n', '      otherwise');\r\nfprintf(fh, '%s \\n', '        error( ''trendy:urlfilter:InvalidState'', ...');\r\nfprintf(fh, '%s \\n', '             [''Encountered unknown state '' state])');\r\nfprintf(fh, '%s \\n', '    end');\r\nfprintf(fh, '%s \\n', '    strIndex = moveIndexFcn(strIndex);');\r\nfprintf(fh, '%s \\n', '    if (strIndex == 0) || (strIndex \u003e urlStrLen)');\r\nfprintf(fh, '%s \\n', '      % We ran off the end of the string.');\r\nfprintf(fh, '%s \\n', '      disp(''End of file reached.'')');\r\nfprintf(fh, '%s \\n', '      break');\r\nfprintf(fh, '%s \\n', '    end');\r\nfprintf(fh, '%s \\n', '  end');\r\nfprintf(fh, '%s \\n', 'end');\r\nfprintf(fh, '%s \\n', '% ==================');\r\nfprintf(fh, '%s \\n', 'function tf = isDigitDotDashOrComma(ch)');\r\nfprintf(fh, '%s \\n', '  tf = ((ch \u003e= ''0'') \u0026\u0026 (ch \u003c= ''9'')) || ...');\r\nfprintf(fh, '%s \\n', '          (ch == ''.'') || (ch == ''-'') || (ch == '','');');\r\nfprintf(fh, '%s \\n', 'end');\r\nfclose(fh);\r\n%%\r\nrehash path\r\n%%\r\ny=solutions();\r\nassert(isequal(mod(y,1),0))\r\n%%\r\ny=solutions();\r\nassert(y\u003e0);\r\n%%\r\ny=solutions();\r\n% yes, yes solution hidden in the test suite... try to code adifferent one! :-)\r\nurl='http://www.mathworks.co.uk/matlabcentral/cody/problems/2312'\r\ny_correct=max([0 cellfun(@(S)str2num(cell2mat(S)),regexp(urlread(url),'\u003cspan class=\"solution_statistic\"\u003e(\\d*)\u003c/span\u003e\u003cspan class=\"text\"\u003e Solutions\u003c/span\u003e','tokens'))]) + 1; % don't forget your solution\r\nt = mtree('solutions.m','-file');\r\nsize = ceil(length(t.nodesize)/13);\r\nfeval(@assignin,'caller','score',abs(y-y_correct)+size);\r\n% (... and solutions will be rescored from time to time :-D)\r\n","published":true,"deleted":false,"likes_count":2,"comments_count":1,"created_by":14358,"edited_by":null,"edited_at":null,"deleted_by":null,"deleted_at":null,"solvers_count":68,"test_suite_updated_at":"2014-05-12T12:02:31.000Z","rescore_all_solutions":false,"group_id":1,"created_at":"2014-05-08T08:33:51.000Z","updated_at":"2026-02-18T14:23:20.000Z","published_at":"2014-05-08T09:06:48.000Z","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\u003eGuess, predict or calculate :-)\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\u003e(You will be scored by the accuracy).\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\u003eUpdate:\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.co.uk/matlabcentral/about/trendy/\\\"\u003e\u003cw:r\u003e\u003cw:t\u003eTRENDY\u003c/w:t\u003e\u003c/w:r\u003e\u003c/w:hyperlink\u003e\u003cw:r\u003e\u003cw:t\u003e \u003c/w:t\u003e\u003c/w:r\u003e\u003cw:hyperlink w:docLocation=\\\"http://www.mathworks.co.uk/matlabcentral/trendy/Tutorial/urlfilter.html\\\"\u003e\u003cw:r\u003e\u003cw:t\u003eis\u003c/w:t\u003e\u003c/w:r\u003e\u003c/w:hyperlink\u003e\u003cw:r\u003e\u003cw:t\u003e here!\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\"}]}"}],"term":"tag:\"trendy\"","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:\"trendy\"","current_player":null,"sort":"map(difficulty_value,0,0,999) asc"},"parser":"MathWorks::Search::Solr::QueryParser","directives":{"term":{"directives":{"tag":[["tag:\"trendy\"","","\"","trendy","\""]]}}},"facets":{"#\u003cMathWorks::Search::Field:0x00007fdd47573df8\u003e":null,"#\u003cMathWorks::Search::Field:0x00007fdd47573d58\u003e":null},"filters":{"#\u003cMathWorks::Search::Field:0x00007fdd475733f8\u003e":"\"cody:problem\""},"fields":{"#\u003cMathWorks::Search::Field:0x00007fdd47574078\u003e":1,"#\u003cMathWorks::Search::Field:0x00007fdd47573fd8\u003e":50,"#\u003cMathWorks::Search::Field:0x00007fdd47573f38\u003e":"map(difficulty_value,0,0,999) asc","#\u003cMathWorks::Search::Field:0x00007fdd47573e98\u003e":"tag:\"trendy\""},"user_query":{"#\u003cMathWorks::Search::Field:0x00007fdd47573e98\u003e":"tag:\"trendy\""},"queried_facets":{}},"query_backend":{"connection":{"configuration":{"index_url":"http://index-op-v2/solr/","query_url":"http://search-op-v2/solr/","direct_access_index_urls":["http://index-op-v2/solr/"],"direct_access_query_urls":["http://search-op-v2/solr/"],"timeout":10,"vhost":"search","exchange":"search.topic","heartbeat":30,"pre_index_mode":false,"host":"rabbitmq-eks","port":5672,"username":"cody-search","password":"78X075ddcV44","virtual_host":"search","indexer":"amqp","http_logging":"true","core":"cody"},"query_connection":{"uri":"http://search-op-v2/solr/cody/","proxy":null,"connection":{"parallel_manager":null,"headers":{"User-Agent":"Faraday v1.0.1"},"params":{},"options":{"params_encoder":"Faraday::FlatParamsEncoder","proxy":null,"bind":null,"timeout":null,"open_timeout":null,"read_timeout":null,"write_timeout":null,"boundary":null,"oauth":null,"context":null,"on_data":null},"ssl":{"verify":true,"ca_file":null,"ca_path":null,"verify_mode":null,"cert_store":null,"client_cert":null,"client_key":null,"certificate":null,"private_key":null,"verify_depth":null,"version":null,"min_version":null,"max_version":null},"default_parallel_manager":null,"builder":{"adapter":{"name":"Faraday::Adapter::NetHttp","args":[],"block":null},"handlers":[{"name":"Faraday::Response::RaiseError","args":[],"block":null}],"app":{"app":{"ssl_cert_store":{"verify_callback":null,"error":null,"error_string":null,"chain":null,"time":null},"app":{},"connection_options":{},"config_block":null}}},"url_prefix":"http://search-op-v2/solr/cody/","manual_proxy":false,"proxy":null},"update_format":"RSolr::JSON::Generator","update_path":"update","options":{"url":"http://search-op-v2/solr/cody"}}},"query":{"params":{"per_page":50,"term":"tag:\"trendy\"","current_player":null,"sort":"map(difficulty_value,0,0,999) asc"},"parser":"MathWorks::Search::Solr::QueryParser","directives":{"term":{"directives":{"tag":[["tag:\"trendy\"","","\"","trendy","\""]]}}},"facets":{"#\u003cMathWorks::Search::Field:0x00007fdd47573df8\u003e":null,"#\u003cMathWorks::Search::Field:0x00007fdd47573d58\u003e":null},"filters":{"#\u003cMathWorks::Search::Field:0x00007fdd475733f8\u003e":"\"cody:problem\""},"fields":{"#\u003cMathWorks::Search::Field:0x00007fdd47574078\u003e":1,"#\u003cMathWorks::Search::Field:0x00007fdd47573fd8\u003e":50,"#\u003cMathWorks::Search::Field:0x00007fdd47573f38\u003e":"map(difficulty_value,0,0,999) asc","#\u003cMathWorks::Search::Field:0x00007fdd47573e98\u003e":"tag:\"trendy\""},"user_query":{"#\u003cMathWorks::Search::Field:0x00007fdd47573e98\u003e":"tag:\"trendy\""},"queried_facets":{}},"options":{"fields":["id","difficulty_rating"]},"join":" "},"results":[{"id":2313,"difficulty_rating":"easy"},{"id":2312,"difficulty_rating":"easy"}]}}