{"group":{"id":1,"name":"Community","lockable":false,"created_at":"2012-01-18T18:02:15.000Z","updated_at":"2026-05-26T00:16:20.000Z","description":"Problems submitted by members of the MATLAB Central community.","is_default":true,"created_by":161519,"badge_id":null,"featured":false,"trending":false,"solution_count_in_trending_period":0,"trending_last_calculated":"2026-05-26T00:00:00.000Z","image_id":null,"published":true,"community_created":false,"status_id":2,"is_default_group_for_player":false,"deleted_by":null,"deleted_at":null,"restored_by":null,"restored_at":null,"description_opc":null,"description_html":null,"published_at":null},"problems":[{"id":44715,"title":"007: Chinese Barrack Invasion","description":"*MISSION:* Successfully invade a military barrack located in China.\r\n\r\n*WARNING:* There is a row of _n_ security switches protecting the military installation entrance. The switches can be manipulated as follows:\r\n\r\n* The rightmost switch may be turned on or off at will.\r\n\r\n* Any other switch may be turned on or off only if the switch to its immediate right is on and all the other switches to its right, if any,\r\nare off.\r\n\r\n* Only one switch may be toggled at a time.\r\n\r\nAll _n_ security switches are currently turned on. Deactivate the security system by turning off all the switches in the minimum number of moves _m_ (toggling one switch is considered one move.) An alarm will be triggered if more than _m_ moves are made. Quickly, determine the minimum number of moves _m_ . \r\n\r\nBe Careful. Do not get caught!!!\r\n\r\n*HINT:* The security system was designed by the Chinese.","description_html":"\u003cp\u003e\u003cb\u003eMISSION:\u003c/b\u003e Successfully invade a military barrack located in China.\u003c/p\u003e\u003cp\u003e\u003cb\u003eWARNING:\u003c/b\u003e There is a row of \u003ci\u003en\u003c/i\u003e security switches protecting the military installation entrance. The switches can be manipulated as follows:\u003c/p\u003e\u003cul\u003e\u003cli\u003eThe rightmost switch may be turned on or off at will.\u003c/li\u003e\u003c/ul\u003e\u003cul\u003e\u003cli\u003eAny other switch may be turned on or off only if the switch to its immediate right is on and all the other switches to its right, if any,\r\nare off.\u003c/li\u003e\u003c/ul\u003e\u003cul\u003e\u003cli\u003eOnly one switch may be toggled at a time.\u003c/li\u003e\u003c/ul\u003e\u003cp\u003eAll \u003ci\u003en\u003c/i\u003e security switches are currently turned on. Deactivate the security system by turning off all the switches in the minimum number of moves \u003ci\u003em\u003c/i\u003e (toggling one switch is considered one move.) An alarm will be triggered if more than \u003ci\u003em\u003c/i\u003e moves are made. Quickly, determine the minimum number of moves \u003ci\u003em\u003c/i\u003e .\u003c/p\u003e\u003cp\u003eBe Careful. Do not get caught!!!\u003c/p\u003e\u003cp\u003e\u003cb\u003eHINT:\u003c/b\u003e The security system was designed by the Chinese.\u003c/p\u003e","function_template":"function m = Invasion(n)\r\n  \r\nend","test_suite":"%%\r\nassert(isequal(Invasion(0),0))\r\n\r\n%%\r\nassert(isequal(Invasion(1),1))\r\n\r\n%%\r\nassert(isequal(Invasion(2),2))\r\n\r\n%%\r\nassert(isequal(Invasion(3),5))\r\n\r\n%%\r\nassert(isequal(Invasion(4),10))\r\n\r\n%%\r\nassert(isequal(Invasion(5),21))\r\n\r\n%%\r\nassert(isequal(Invasion(6),42))\r\n\r\n%%\r\nassert(isequal(Invasion(7),85))\r\n\r\n%%\r\nassert(isequal(Invasion(8),170))\r\n\r\n%%\r\nassert(isequal(Invasion(9),341))\r\n\r\n%%\r\nassert(isequal(Invasion(10),682))\r\n\r\n%%\r\nassert(isequal(Invasion(11),1365))\r\n\r\n%%\r\nassert(isequal(Invasion(12),2730))","published":true,"deleted":false,"likes_count":2,"comments_count":0,"created_by":178544,"edited_by":null,"edited_at":null,"deleted_by":null,"deleted_at":null,"solvers_count":23,"test_suite_updated_at":"2018-09-07T18:01:16.000Z","rescore_all_solutions":false,"group_id":1,"created_at":"2018-08-04T14:29:49.000Z","updated_at":"2025-12-16T03:09:27.000Z","published_at":"2018-08-04T14:32:20.000Z","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:rPr\u003e\u003cw:b/\u003e\u003c/w:rPr\u003e\u003cw:t\u003eMISSION:\u003c/w:t\u003e\u003c/w:r\u003e\u003cw:r\u003e\u003cw:t\u003e Successfully invade a military barrack located in China.\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:rPr\u003e\u003cw:b/\u003e\u003c/w:rPr\u003e\u003cw:t\u003eWARNING:\u003c/w:t\u003e\u003c/w:r\u003e\u003cw:r\u003e\u003cw:t\u003e There is a row of\u003c/w:t\u003e\u003c/w:r\u003e\u003cw:r\u003e\u003cw:t\u003e \u003c/w:t\u003e\u003c/w:r\u003e\u003cw:r\u003e\u003cw:rPr\u003e\u003cw:i/\u003e\u003c/w:rPr\u003e\u003cw:t\u003en\u003c/w:t\u003e\u003c/w:r\u003e\u003cw:r\u003e\u003cw:t\u003e security switches protecting the military installation entrance. The switches can be manipulated as follows:\u003c/w:t\u003e\u003c/w:r\u003e\u003c/w:p\u003e\u003cw:p\u003e\u003cw:pPr\u003e\u003cw:pStyle w:val=\\\"ListParagraph\\\"/\u003e\u003cw:numPr\u003e\u003cw:numId w:val=\\\"1\\\"/\u003e\u003c/w:numPr\u003e\u003c/w:pPr\u003e\u003cw:r\u003e\u003cw:t\u003eThe rightmost switch may be turned on or off at will.\u003c/w:t\u003e\u003c/w:r\u003e\u003c/w:p\u003e\u003cw:p\u003e\u003cw:pPr\u003e\u003cw:pStyle w:val=\\\"ListParagraph\\\"/\u003e\u003cw:numPr\u003e\u003cw:numId w:val=\\\"1\\\"/\u003e\u003c/w:numPr\u003e\u003c/w:pPr\u003e\u003cw:r\u003e\u003cw:t\u003eAny other switch may be turned on or off only if the switch to its immediate right is on and all the other switches to its right, if any,are off.\u003c/w:t\u003e\u003c/w:r\u003e\u003c/w:p\u003e\u003cw:p\u003e\u003cw:pPr\u003e\u003cw:pStyle w:val=\\\"ListParagraph\\\"/\u003e\u003cw:numPr\u003e\u003cw:numId w:val=\\\"1\\\"/\u003e\u003c/w:numPr\u003e\u003c/w:pPr\u003e\u003cw:r\u003e\u003cw:t\u003eOnly one switch may be toggled at a time.\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\u003eAll\u003c/w:t\u003e\u003c/w:r\u003e\u003cw:r\u003e\u003cw:t\u003e \u003c/w:t\u003e\u003c/w:r\u003e\u003cw:r\u003e\u003cw:rPr\u003e\u003cw:i/\u003e\u003c/w:rPr\u003e\u003cw:t\u003en\u003c/w:t\u003e\u003c/w:r\u003e\u003cw:r\u003e\u003cw:t\u003e security switches are currently turned on. Deactivate the security system by turning off all the switches in the minimum number of moves\u003c/w:t\u003e\u003c/w:r\u003e\u003cw:r\u003e\u003cw:t\u003e \u003c/w:t\u003e\u003c/w:r\u003e\u003cw:r\u003e\u003cw:rPr\u003e\u003cw:i/\u003e\u003c/w:rPr\u003e\u003cw:t\u003em\u003c/w:t\u003e\u003c/w:r\u003e\u003cw:r\u003e\u003cw:t\u003e (toggling one switch is considered one move.) An alarm will be triggered if more than\u003c/w:t\u003e\u003c/w:r\u003e\u003cw:r\u003e\u003cw:t\u003e \u003c/w:t\u003e\u003c/w:r\u003e\u003cw:r\u003e\u003cw:rPr\u003e\u003cw:i/\u003e\u003c/w:rPr\u003e\u003cw:t\u003em\u003c/w:t\u003e\u003c/w:r\u003e\u003cw:r\u003e\u003cw:t\u003e moves are made. Quickly, determine the minimum number of moves\u003c/w:t\u003e\u003c/w:r\u003e\u003cw:r\u003e\u003cw:t\u003e \u003c/w:t\u003e\u003c/w:r\u003e\u003cw:r\u003e\u003cw:rPr\u003e\u003cw:i/\u003e\u003c/w:rPr\u003e\u003cw:t\u003em\u003c/w:t\u003e\u003c/w:r\u003e\u003cw:r\u003e\u003cw:t\u003e .\u003c/w:t\u003e\u003c/w:r\u003e\u003c/w:p\u003e\u003cw:p\u003e\u003cw:pPr\u003e\u003cw:pStyle w:val=\\\"text\\\"/\u003e\u003c/w:pPr\u003e\u003cw:r\u003e\u003cw:t\u003eBe Careful. Do not get caught!!!\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:rPr\u003e\u003cw:b/\u003e\u003c/w:rPr\u003e\u003cw:t\u003eHINT:\u003c/w:t\u003e\u003c/w:r\u003e\u003cw:r\u003e\u003cw:t\u003e The security system was designed by the Chinese.\u003c/w:t\u003e\u003c/w:r\u003e\u003c/w:p\u003e\u003c/w:body\u003e\u003c/w:document\u003e\"},{\"partUri\":\"/matlab/output.xml\",\"contentType\":\"text/xml\",\"content\":\"\u003c?xml version=\\\"1.0\\\" encoding=\\\"UTF-8\\\" standalone=\\\"no\\\" ?\u003e\u003cembeddedOutputs\u003e\u003cmetaData\u003e\u003cevaluationState\u003emanual\u003c/evaluationState\u003e\u003clayoutState\u003ecode\u003c/layoutState\u003e\u003coutputStatus\u003eready\u003c/outputStatus\u003e\u003c/metaData\u003e\u003coutputArray type=\\\"array\\\"/\u003e\u003cregionArray type=\\\"array\\\"/\u003e\u003c/embeddedOutputs\u003e\"}]}"}],"problem_search":{"problems":[{"id":44715,"title":"007: Chinese Barrack Invasion","description":"*MISSION:* Successfully invade a military barrack located in China.\r\n\r\n*WARNING:* There is a row of _n_ security switches protecting the military installation entrance. The switches can be manipulated as follows:\r\n\r\n* The rightmost switch may be turned on or off at will.\r\n\r\n* Any other switch may be turned on or off only if the switch to its immediate right is on and all the other switches to its right, if any,\r\nare off.\r\n\r\n* Only one switch may be toggled at a time.\r\n\r\nAll _n_ security switches are currently turned on. Deactivate the security system by turning off all the switches in the minimum number of moves _m_ (toggling one switch is considered one move.) An alarm will be triggered if more than _m_ moves are made. Quickly, determine the minimum number of moves _m_ . \r\n\r\nBe Careful. Do not get caught!!!\r\n\r\n*HINT:* The security system was designed by the Chinese.","description_html":"\u003cp\u003e\u003cb\u003eMISSION:\u003c/b\u003e Successfully invade a military barrack located in China.\u003c/p\u003e\u003cp\u003e\u003cb\u003eWARNING:\u003c/b\u003e There is a row of \u003ci\u003en\u003c/i\u003e security switches protecting the military installation entrance. The switches can be manipulated as follows:\u003c/p\u003e\u003cul\u003e\u003cli\u003eThe rightmost switch may be turned on or off at will.\u003c/li\u003e\u003c/ul\u003e\u003cul\u003e\u003cli\u003eAny other switch may be turned on or off only if the switch to its immediate right is on and all the other switches to its right, if any,\r\nare off.\u003c/li\u003e\u003c/ul\u003e\u003cul\u003e\u003cli\u003eOnly one switch may be toggled at a time.\u003c/li\u003e\u003c/ul\u003e\u003cp\u003eAll \u003ci\u003en\u003c/i\u003e security switches are currently turned on. Deactivate the security system by turning off all the switches in the minimum number of moves \u003ci\u003em\u003c/i\u003e (toggling one switch is considered one move.) An alarm will be triggered if more than \u003ci\u003em\u003c/i\u003e moves are made. Quickly, determine the minimum number of moves \u003ci\u003em\u003c/i\u003e .\u003c/p\u003e\u003cp\u003eBe Careful. Do not get caught!!!\u003c/p\u003e\u003cp\u003e\u003cb\u003eHINT:\u003c/b\u003e The security system was designed by the Chinese.\u003c/p\u003e","function_template":"function m = Invasion(n)\r\n  \r\nend","test_suite":"%%\r\nassert(isequal(Invasion(0),0))\r\n\r\n%%\r\nassert(isequal(Invasion(1),1))\r\n\r\n%%\r\nassert(isequal(Invasion(2),2))\r\n\r\n%%\r\nassert(isequal(Invasion(3),5))\r\n\r\n%%\r\nassert(isequal(Invasion(4),10))\r\n\r\n%%\r\nassert(isequal(Invasion(5),21))\r\n\r\n%%\r\nassert(isequal(Invasion(6),42))\r\n\r\n%%\r\nassert(isequal(Invasion(7),85))\r\n\r\n%%\r\nassert(isequal(Invasion(8),170))\r\n\r\n%%\r\nassert(isequal(Invasion(9),341))\r\n\r\n%%\r\nassert(isequal(Invasion(10),682))\r\n\r\n%%\r\nassert(isequal(Invasion(11),1365))\r\n\r\n%%\r\nassert(isequal(Invasion(12),2730))","published":true,"deleted":false,"likes_count":2,"comments_count":0,"created_by":178544,"edited_by":null,"edited_at":null,"deleted_by":null,"deleted_at":null,"solvers_count":23,"test_suite_updated_at":"2018-09-07T18:01:16.000Z","rescore_all_solutions":false,"group_id":1,"created_at":"2018-08-04T14:29:49.000Z","updated_at":"2025-12-16T03:09:27.000Z","published_at":"2018-08-04T14:32:20.000Z","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:rPr\u003e\u003cw:b/\u003e\u003c/w:rPr\u003e\u003cw:t\u003eMISSION:\u003c/w:t\u003e\u003c/w:r\u003e\u003cw:r\u003e\u003cw:t\u003e Successfully invade a military barrack located in China.\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:rPr\u003e\u003cw:b/\u003e\u003c/w:rPr\u003e\u003cw:t\u003eWARNING:\u003c/w:t\u003e\u003c/w:r\u003e\u003cw:r\u003e\u003cw:t\u003e There is a row of\u003c/w:t\u003e\u003c/w:r\u003e\u003cw:r\u003e\u003cw:t\u003e \u003c/w:t\u003e\u003c/w:r\u003e\u003cw:r\u003e\u003cw:rPr\u003e\u003cw:i/\u003e\u003c/w:rPr\u003e\u003cw:t\u003en\u003c/w:t\u003e\u003c/w:r\u003e\u003cw:r\u003e\u003cw:t\u003e security switches protecting the military installation entrance. The switches can be manipulated as follows:\u003c/w:t\u003e\u003c/w:r\u003e\u003c/w:p\u003e\u003cw:p\u003e\u003cw:pPr\u003e\u003cw:pStyle w:val=\\\"ListParagraph\\\"/\u003e\u003cw:numPr\u003e\u003cw:numId w:val=\\\"1\\\"/\u003e\u003c/w:numPr\u003e\u003c/w:pPr\u003e\u003cw:r\u003e\u003cw:t\u003eThe rightmost switch may be turned on or off at will.\u003c/w:t\u003e\u003c/w:r\u003e\u003c/w:p\u003e\u003cw:p\u003e\u003cw:pPr\u003e\u003cw:pStyle w:val=\\\"ListParagraph\\\"/\u003e\u003cw:numPr\u003e\u003cw:numId w:val=\\\"1\\\"/\u003e\u003c/w:numPr\u003e\u003c/w:pPr\u003e\u003cw:r\u003e\u003cw:t\u003eAny other switch may be turned on or off only if the switch to its immediate right is on and all the other switches to its right, if any,are off.\u003c/w:t\u003e\u003c/w:r\u003e\u003c/w:p\u003e\u003cw:p\u003e\u003cw:pPr\u003e\u003cw:pStyle w:val=\\\"ListParagraph\\\"/\u003e\u003cw:numPr\u003e\u003cw:numId w:val=\\\"1\\\"/\u003e\u003c/w:numPr\u003e\u003c/w:pPr\u003e\u003cw:r\u003e\u003cw:t\u003eOnly one switch may be toggled at a time.\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\u003eAll\u003c/w:t\u003e\u003c/w:r\u003e\u003cw:r\u003e\u003cw:t\u003e \u003c/w:t\u003e\u003c/w:r\u003e\u003cw:r\u003e\u003cw:rPr\u003e\u003cw:i/\u003e\u003c/w:rPr\u003e\u003cw:t\u003en\u003c/w:t\u003e\u003c/w:r\u003e\u003cw:r\u003e\u003cw:t\u003e security switches are currently turned on. Deactivate the security system by turning off all the switches in the minimum number of moves\u003c/w:t\u003e\u003c/w:r\u003e\u003cw:r\u003e\u003cw:t\u003e \u003c/w:t\u003e\u003c/w:r\u003e\u003cw:r\u003e\u003cw:rPr\u003e\u003cw:i/\u003e\u003c/w:rPr\u003e\u003cw:t\u003em\u003c/w:t\u003e\u003c/w:r\u003e\u003cw:r\u003e\u003cw:t\u003e (toggling one switch is considered one move.) An alarm will be triggered if more than\u003c/w:t\u003e\u003c/w:r\u003e\u003cw:r\u003e\u003cw:t\u003e \u003c/w:t\u003e\u003c/w:r\u003e\u003cw:r\u003e\u003cw:rPr\u003e\u003cw:i/\u003e\u003c/w:rPr\u003e\u003cw:t\u003em\u003c/w:t\u003e\u003c/w:r\u003e\u003cw:r\u003e\u003cw:t\u003e moves are made. Quickly, determine the minimum number of moves\u003c/w:t\u003e\u003c/w:r\u003e\u003cw:r\u003e\u003cw:t\u003e \u003c/w:t\u003e\u003c/w:r\u003e\u003cw:r\u003e\u003cw:rPr\u003e\u003cw:i/\u003e\u003c/w:rPr\u003e\u003cw:t\u003em\u003c/w:t\u003e\u003c/w:r\u003e\u003cw:r\u003e\u003cw:t\u003e .\u003c/w:t\u003e\u003c/w:r\u003e\u003c/w:p\u003e\u003cw:p\u003e\u003cw:pPr\u003e\u003cw:pStyle w:val=\\\"text\\\"/\u003e\u003c/w:pPr\u003e\u003cw:r\u003e\u003cw:t\u003eBe Careful. Do not get caught!!!\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:rPr\u003e\u003cw:b/\u003e\u003c/w:rPr\u003e\u003cw:t\u003eHINT:\u003c/w:t\u003e\u003c/w:r\u003e\u003cw:r\u003e\u003cw:t\u003e The security system was designed by the Chinese.\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\"}]}"}],"errors":[],"facets":[[],[{"value":"medium","count":1,"selected":false}]],"term":"tag:\"gary code\"","page":1,"per_page":50,"sort":"map(difficulty_value,0,0,999) asc"}}