{"group":{"id":1,"name":"Community","lockable":false,"created_at":"2012-01-18T18:02:15.000Z","updated_at":"2026-04-26T00:14:02.000Z","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":"2026-04-26T00:00:00.000Z","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":60760,"title":"Find the closest canyon prime","description":"My wife and I celebrated our honeymoon and most recent anniversary in Yellowstone and Grand Teton National Parks. After returning from our latest trip, I made her a word puzzle involving geysers, mud pots, and canyons. Because canyons form when rock erodes and walls remain, a canyon in the puzzle was a word that could erode two or more letters from the interior to form a new word, leaving at least one of the original letters on each side. For example, if TOPLAS is eroded from PROTOPLASM, then PROM is formed.\r\nThis problem deals with canyon primes, defined as a prime number that can erode two or more consecutive interior digits, leaving at least one original digit on each side, and become a new prime. 4813 and 4817 are both canyon primes because eroding 81 from both leaves 43 and 47, which are prime. 29411 is a canyon prime because eroding 94 leaves 211, which is prime. 299623 is a canyon prime because eroding 996 leaves 223, which is prime.\r\nWrite a function that produces the canyon prime closest to the input number. If two numbers are equally distant from the input, choose the smaller.","description_html":"\u003cdiv style = \"text-align: start; line-height: 20.44px; min-height: 0px; white-space: normal; color: rgb(0, 0, 0); font-family: Menlo, Monaco, Consolas, monospace; font-style: normal; font-size: 14px; font-weight: 400; text-decoration: none solid rgb(0, 0, 0); white-space: normal; \"\u003e\u003cdiv style=\"block-size: 249px; display: block; min-width: 0px; padding-block-start: 0px; padding-top: 0px; perspective-origin: 407px 124.5px; transform-origin: 407px 124.5px; vertical-align: baseline; \"\u003e\u003cdiv style=\"block-size: 105px; font-family: Helvetica, Arial, sans-serif; line-height: 21px; margin-block-end: 9px; margin-block-start: 2px; margin-bottom: 9px; margin-inline-end: 10px; margin-inline-start: 4px; margin-left: 4px; margin-right: 10px; margin-top: 2px; perspective-origin: 384px 52.5px; text-align: left; transform-origin: 384px 52.5px; white-space-collapse: preserve; margin-left: 4px; margin-top: 2px; margin-bottom: 9px; margin-right: 10px; \"\u003e\u003cspan style=\"block-size: auto; display: inline; margin-block-end: 0px; margin-block-start: 0px; margin-bottom: 0px; margin-inline-end: 0px; margin-inline-start: 0px; margin-left: 0px; margin-right: 0px; margin-top: 0px; perspective-origin: 0px 0px; transform-origin: 0px 0px; unicode-bidi: normal; \"\u003e\u003cspan style=\"\"\u003eMy wife and I celebrated our honeymoon and most recent anniversary in Yellowstone and Grand Teton National Parks. After returning from our latest trip, I made her a word puzzle involving geysers, mud pots, and canyons. Because canyons form when rock erodes and walls remain, a canyon in the puzzle was a word that could erode two or more letters from the interior to form a new word, leaving at least one of the original letters on each side. For example, if TOPLAS is eroded from PROTOPLASM, then PROM is formed.\u003c/span\u003e\u003c/span\u003e\u003c/div\u003e\u003cdiv style=\"block-size: 84px; font-family: Helvetica, Arial, sans-serif; line-height: 21px; margin-block-end: 9px; margin-block-start: 2px; margin-bottom: 9px; margin-inline-end: 10px; margin-inline-start: 4px; margin-left: 4px; margin-right: 10px; margin-top: 2px; perspective-origin: 384px 42px; text-align: left; transform-origin: 384px 42px; white-space-collapse: preserve; margin-left: 4px; margin-top: 2px; margin-bottom: 9px; margin-right: 10px; \"\u003e\u003cspan style=\"block-size: auto; display: inline; margin-block-end: 0px; margin-block-start: 0px; margin-bottom: 0px; margin-inline-end: 0px; margin-inline-start: 0px; margin-left: 0px; margin-right: 0px; margin-top: 0px; perspective-origin: 0px 0px; transform-origin: 0px 0px; unicode-bidi: normal; \"\u003e\u003cspan style=\"\"\u003eThis problem deals with \u003c/span\u003e\u003c/span\u003e\u003cspan style=\"block-size: auto; display: inline; margin-block-end: 0px; margin-block-start: 0px; margin-bottom: 0px; margin-inline-end: 0px; margin-inline-start: 0px; margin-left: 0px; margin-right: 0px; margin-top: 0px; perspective-origin: 0px 0px; transform-origin: 0px 0px; unicode-bidi: normal; \"\u003e\u003cspan style=\"font-style: italic; \"\u003ecanyon primes\u003c/span\u003e\u003c/span\u003e\u003cspan style=\"block-size: auto; display: inline; margin-block-end: 0px; margin-block-start: 0px; margin-bottom: 0px; margin-inline-end: 0px; margin-inline-start: 0px; margin-left: 0px; margin-right: 0px; margin-top: 0px; perspective-origin: 0px 0px; transform-origin: 0px 0px; unicode-bidi: normal; \"\u003e\u003cspan style=\"\"\u003e, defined as a prime number that can erode two or more consecutive interior digits, leaving at least one original digit on each side, and become a new prime. 4813 and 4817 are both canyon primes because eroding 81 from both leaves 43 and 47, which are prime. 29411 is a canyon prime because eroding 94 leaves 211, which is prime. 299623 is a canyon prime because eroding 996 leaves 223, which is prime.\u003c/span\u003e\u003c/span\u003e\u003c/div\u003e\u003cdiv style=\"block-size: 42px; font-family: Helvetica, Arial, sans-serif; line-height: 21px; margin-block-end: 9px; margin-block-start: 2px; margin-bottom: 9px; margin-inline-end: 10px; margin-inline-start: 4px; margin-left: 4px; margin-right: 10px; margin-top: 2px; perspective-origin: 384px 21px; text-align: left; transform-origin: 384px 21px; white-space-collapse: preserve; margin-left: 4px; margin-top: 2px; margin-bottom: 9px; margin-right: 10px; \"\u003e\u003cspan style=\"block-size: auto; display: inline; margin-block-end: 0px; margin-block-start: 0px; margin-bottom: 0px; margin-inline-end: 0px; margin-inline-start: 0px; margin-left: 0px; margin-right: 0px; margin-top: 0px; perspective-origin: 0px 0px; transform-origin: 0px 0px; unicode-bidi: normal; \"\u003e\u003cspan style=\"\"\u003eWrite a function that produces the canyon prime closest to the input number. If two numbers are equally distant from the input, choose the smaller.\u003c/span\u003e\u003c/span\u003e\u003c/div\u003e\u003c/div\u003e\u003c/div\u003e","function_template":"function y = closestCanyonPrime(x)\r\n  y = min(dist(x-primes(x)));\r\nend","test_suite":"%%\r\nx = 1:1011;\r\ny = arrayfun(@closestCanyonPrime,x);\r\nassert(all(y==1009))\r\n\r\n%%\r\nx = 1500;\r\ny = closestCanyonPrime(x);\r\ny_correct = 1499;\r\nassert(isequal(y,y_correct))\r\n\r\n%%\r\nx = 4513;\r\ny = closestCanyonPrime(x);\r\ny_correct = 4513;\r\nassert(isequal(y,y_correct))\r\n\r\n%%\r\nx = 8300;\r\ny = closestCanyonPrime(x);\r\ny_correct = 8293;\r\nassert(isequal(y,y_correct))\r\n\r\n%%\r\nx = 62586;\r\ny = closestCanyonPrime(x);\r\ny_correct = 62581;\r\nassert(isequal(y,y_correct))\r\n\r\n%%\r\nx = 99849;\r\ny = closestCanyonPrime(x);\r\ny_correct = 99829;\r\nassert(isequal(y,y_correct))\r\n\r\n%%\r\nx = 103000;\r\ny = closestCanyonPrime(x);\r\ny_correct = 103001;\r\nassert(isequal(y,y_correct))\r\n\r\n%%\r\nx = 203000;\r\ny = closestCanyonPrime(x);\r\ny_correct = 202999;\r\nassert(isequal(y,y_correct))\r\n\r\n%%\r\nx = 465200;\r\ny = closestCanyonPrime(x);\r\ny_correct = 465209;\r\nassert(isequal(y,y_correct))\r\n\r\n%%\r\nx = 888888;\r\ny = closestCanyonPrime(x);\r\ny_correct = 888887;\r\nassert(isequal(y,y_correct))\r\n\r\n%%\r\nx = 1e7;\r\ny = closestCanyonPrime(x);\r\ny_correct = 9999991;\r\nassert(isequal(y,y_correct))\r\n\r\n%%\r\nx = 5e8;\r\ny = closestCanyonPrime(x);\r\ny_correct = 500000003;\r\nassert(isequal(y,y_correct))","published":true,"deleted":false,"likes_count":0,"comments_count":3,"created_by":46909,"edited_by":46909,"edited_at":"2024-11-22T14:28:24.000Z","deleted_by":null,"deleted_at":null,"solvers_count":5,"test_suite_updated_at":null,"rescore_all_solutions":false,"group_id":1,"created_at":"2024-11-11T04:30:55.000Z","updated_at":"2025-07-23T20:49:51.000Z","published_at":"2024-11-11T04:31:10.000Z","restored_at":null,"restored_by":null,"spam":null,"simulink":false,"admin_reviewed":false,"description_opc":"{\"parts\":[{\"partUri\":\"/matlab/document.xml\",\"contentType\":\"application/vnd.mathworks.matlab.code.document+xml\",\"content\":\"\u003c?xml version=\\\"1.0\\\" encoding=\\\"UTF-8\\\"?\u003e\u003cw:document xmlns:w=\\\"http://schemas.openxmlformats.org/wordprocessingml/2006/main\\\"\u003e\u003cw:body\u003e\u003cw:p\u003e\u003cw:pPr\u003e\u003cw:pStyle w:val=\\\"text\\\"/\u003e\u003cw:jc w:val=\\\"left\\\"/\u003e\u003c/w:pPr\u003e\u003cw:r\u003e\u003cw:t\u003eMy wife and I celebrated our honeymoon and most recent anniversary in Yellowstone and Grand Teton National Parks. After returning from our latest trip, I made her a word puzzle involving geysers, mud pots, and canyons. Because canyons form when rock erodes and walls remain, a canyon in the puzzle was a word that could erode two or more letters from the interior to form a new word, leaving at least one of the original letters on each side. For example, if TOPLAS is eroded from PROTOPLASM, then PROM is formed.\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\u003eThis problem deals with \u003c/w:t\u003e\u003c/w:r\u003e\u003cw:r\u003e\u003cw:rPr\u003e\u003cw:i/\u003e\u003c/w:rPr\u003e\u003cw:t\u003ecanyon primes\u003c/w:t\u003e\u003c/w:r\u003e\u003cw:r\u003e\u003cw:t\u003e, defined as a prime number that can erode two or more consecutive interior digits, leaving at least one original digit on each side, and become a new prime. 4813 and 4817 are both canyon primes because eroding 81 from both leaves 43 and 47, which are prime. 29411 is a canyon prime because eroding 94 leaves 211, which is prime. 299623 is a canyon prime because eroding 996 leaves 223, which is prime.\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\u003eWrite a function that produces the canyon prime closest to the input number. If two numbers are equally distant from the input, choose the smaller.\u003c/w:t\u003e\u003c/w:r\u003e\u003c/w:p\u003e\u003c/w:body\u003e\u003c/w:document\u003e\",\"relationship\":null}],\"relationships\":[{\"relationshipType\":\"http://schemas.mathworks.com/matlab/code/2013/relationships/document\",\"target\":\"/matlab/document.xml\",\"relationshipId\":\"rId1\"}]}"},{"id":60733,"title":"Find the closest geyser prime","description":"My wife and I celebrated our honeymoon and our recent anniversary in Yellowstone and Grand Teton National Parks. After returning from our latest trip, I made her a word puzzle involving geysers, mud pots, and canyons. Because geysers eject water and gases, a geyser in the puzzle was a word that could eject a single letter and become a new word. For example, SHORT could eject H and become SORT. \r\nThis problem deals with geyser primes, defined as prime numbers that can eject only one of their digits and become new primes. 263 is a geyser prime because it can eject the 6 (and only the 6) and become the prime 23. 10007 is a geyser prime because ejecting the 1 leads to 7 (ignore leading zeros). 251 is not a geyser prime because none of 51, 21, and 25 is prime. 197 is not a geyser prime because it can eject any one of its digits and result in a prime (97, 17, or 19). 233 is not a geyser prime because ejecting either of the 3s results in a prime. Remember that 1 is neither prime nor composite and notice the difference between geyser primes and delete-a-digit primes. \r\nWrite a function that produces the geyser prime closest to the input number. If two numbers are equally distant from the input, choose the smaller. ","description_html":"\u003cdiv style = \"text-align: start; line-height: 20.44px; min-height: 0px; white-space: normal; color: rgb(0, 0, 0); font-family: Menlo, Monaco, Consolas, monospace; font-style: normal; font-size: 14px; font-weight: 400; text-decoration: none solid rgb(0, 0, 0); white-space: normal; \"\u003e\u003cdiv style=\"block-size: 270px; display: block; min-width: 0px; padding-block-start: 0px; padding-top: 0px; perspective-origin: 407px 135px; transform-origin: 407px 135px; vertical-align: baseline; \"\u003e\u003cdiv style=\"block-size: 84px; font-family: Helvetica, Arial, sans-serif; line-height: 21px; margin-block-end: 9px; margin-block-start: 2px; margin-bottom: 9px; margin-inline-end: 10px; margin-inline-start: 4px; margin-left: 4px; margin-right: 10px; margin-top: 2px; perspective-origin: 384px 42px; text-align: left; transform-origin: 384px 42px; white-space-collapse: preserve; margin-left: 4px; margin-top: 2px; margin-bottom: 9px; margin-right: 10px; \"\u003e\u003cspan style=\"block-size: auto; display: inline; margin-block-end: 0px; margin-block-start: 0px; margin-bottom: 0px; margin-inline-end: 0px; margin-inline-start: 0px; margin-left: 0px; margin-right: 0px; margin-top: 0px; perspective-origin: 0px 0px; transform-origin: 0px 0px; unicode-bidi: normal; \"\u003e\u003cspan style=\"\"\u003eMy wife and I celebrated our honeymoon and our recent anniversary in Yellowstone and Grand Teton National Parks. After returning from our latest trip, I made her a word puzzle involving geysers, mud pots, and canyons. Because \u003c/span\u003e\u003c/span\u003e\u003ca target='_blank' href = \"https://www.youtube.com/watch?v=p3pI3K6CLSY\"\u003e\u003cspan style=\"\"\u003e\u003cspan style=\"\"\u003egeysers eject water and gases\u003c/span\u003e\u003c/span\u003e\u003c/a\u003e\u003cspan style=\"block-size: auto; display: inline; margin-block-end: 0px; margin-block-start: 0px; margin-bottom: 0px; margin-inline-end: 0px; margin-inline-start: 0px; margin-left: 0px; margin-right: 0px; margin-top: 0px; perspective-origin: 0px 0px; transform-origin: 0px 0px; unicode-bidi: normal; \"\u003e\u003cspan style=\"\"\u003e, a geyser in the puzzle was a word that could eject a single letter and become a new word. For example, SHORT could eject H and become SORT. \u003c/span\u003e\u003c/span\u003e\u003c/div\u003e\u003cdiv style=\"block-size: 126px; font-family: Helvetica, Arial, sans-serif; line-height: 21px; margin-block-end: 9px; margin-block-start: 2px; margin-bottom: 9px; margin-inline-end: 10px; margin-inline-start: 4px; margin-left: 4px; margin-right: 10px; margin-top: 2px; perspective-origin: 384px 63px; text-align: left; transform-origin: 384px 63px; white-space-collapse: preserve; margin-left: 4px; margin-top: 2px; margin-bottom: 9px; margin-right: 10px; \"\u003e\u003cspan style=\"block-size: auto; display: inline; margin-block-end: 0px; margin-block-start: 0px; margin-bottom: 0px; margin-inline-end: 0px; margin-inline-start: 0px; margin-left: 0px; margin-right: 0px; margin-top: 0px; perspective-origin: 0px 0px; transform-origin: 0px 0px; unicode-bidi: normal; \"\u003e\u003cspan style=\"\"\u003eThis problem deals with \u003c/span\u003e\u003c/span\u003e\u003cspan style=\"block-size: auto; display: inline; margin-block-end: 0px; margin-block-start: 0px; margin-bottom: 0px; margin-inline-end: 0px; margin-inline-start: 0px; margin-left: 0px; margin-right: 0px; margin-top: 0px; perspective-origin: 0px 0px; transform-origin: 0px 0px; unicode-bidi: normal; \"\u003e\u003cspan style=\"font-style: italic; \"\u003egeyser primes\u003c/span\u003e\u003c/span\u003e\u003cspan style=\"block-size: auto; display: inline; margin-block-end: 0px; margin-block-start: 0px; margin-bottom: 0px; margin-inline-end: 0px; margin-inline-start: 0px; margin-left: 0px; margin-right: 0px; margin-top: 0px; perspective-origin: 0px 0px; transform-origin: 0px 0px; unicode-bidi: normal; \"\u003e\u003cspan style=\"\"\u003e, defined as prime numbers that can eject only one of their digits and become new primes. 263 is a geyser prime because it can eject the 6 (and only the 6) and become the prime 23. 10007 is a geyser prime because ejecting the 1 leads to 7 (ignore leading zeros). 251 is not a geyser prime because none of 51, 21, and 25 is prime. 197 is not a geyser prime because it can eject any one of its digits and result in a prime (97, 17, or 19). 233 is not a geyser prime because ejecting either of the 3s results in a prime. Remember that 1 is neither prime nor composite and notice the difference between geyser primes and \u003c/span\u003e\u003c/span\u003e\u003ca target='_blank' href = \"https://www.mathworks.com/matlabcentral/cody/problems/47833-list-the-delete-a-digit-primes\"\u003e\u003cspan style=\"\"\u003e\u003cspan style=\"text-decoration: underline; text-decoration-line: underline; \"\u003edelete-a-digit primes\u003c/span\u003e\u003c/span\u003e\u003c/a\u003e\u003cspan style=\"block-size: auto; display: inline; margin-block-end: 0px; margin-block-start: 0px; margin-bottom: 0px; margin-inline-end: 0px; margin-inline-start: 0px; margin-left: 0px; margin-right: 0px; margin-top: 0px; perspective-origin: 0px 0px; transform-origin: 0px 0px; unicode-bidi: normal; \"\u003e\u003cspan style=\"\"\u003e. \u003c/span\u003e\u003c/span\u003e\u003c/div\u003e\u003cdiv style=\"block-size: 42px; font-family: Helvetica, Arial, sans-serif; line-height: 21px; margin-block-end: 9px; margin-block-start: 2px; margin-bottom: 9px; margin-inline-end: 10px; margin-inline-start: 4px; margin-left: 4px; margin-right: 10px; margin-top: 2px; perspective-origin: 384px 21px; text-align: left; transform-origin: 384px 21px; white-space-collapse: preserve; margin-left: 4px; margin-top: 2px; margin-bottom: 9px; margin-right: 10px; \"\u003e\u003cspan style=\"block-size: auto; display: inline; margin-block-end: 0px; margin-block-start: 0px; margin-bottom: 0px; margin-inline-end: 0px; margin-inline-start: 0px; margin-left: 0px; margin-right: 0px; margin-top: 0px; perspective-origin: 0px 0px; transform-origin: 0px 0px; unicode-bidi: normal; \"\u003e\u003cspan style=\"\"\u003eWrite a function that produces the geyser prime closest to the input number. If two numbers are equally distant from the input, choose the smaller. \u003c/span\u003e\u003c/span\u003e\u003c/div\u003e\u003c/div\u003e\u003c/div\u003e","function_template":"function y = closestGeyserPrime(x)\r\n  y = min(abs(primes(x)-x));\r\nend","test_suite":"%%\r\nx = 1:15;\r\ny = arrayfun(@closestGeyserPrime,x);\r\nassert(all(y==13))\r\n\r\n%%\r\nx = 45;\r\ny = closestGeyserPrime(x);\r\ny_correct = 43;\r\nassert(isequal(y,y_correct))\r\n\r\n%%\r\nx = 197;\r\ny = closestGeyserPrime(x);\r\ny_correct = 211;\r\nassert(isequal(y,y_correct))\r\n\r\n%%\r\nx = 233;\r\ny = closestGeyserPrime(x);\r\ny_correct = 241;\r\nassert(isequal(y,y_correct))\r\n\r\n%%\r\nx = 251;\r\ny = closestGeyserPrime(x);\r\ny_correct = 241;\r\nassert(isequal(y,y_correct))\r\n\r\n%%\r\nx = 260;\r\ny = closestGeyserPrime(x);\r\ny_correct = 263;\r\nassert(isequal(y,y_correct))\r\n\r\n%%\r\nx = 586;\r\ny = closestGeyserPrime(x);\r\ny_correct = 571;\r\nassert(isequal(y,y_correct))\r\n\r\n%%\r\nx = 587;\r\ny = closestGeyserPrime(x);\r\ny_correct = 601;\r\nassert(isequal(y,y_correct))\r\n\r\n%%\r\nx = 1500;\r\ny = closestGeyserPrime(x);\r\ny_correct = 1489;\r\nassert(isequal(y,y_correct))\r\n\r\n%%\r\nx = 4511;\r\ny = closestGeyserPrime(x);\r\ny_correct = 4507;\r\nassert(isequal(y,y_correct))\r\n\r\n%%\r\nx = 8300;\r\ny = closestGeyserPrime(x);\r\ny_correct = 8317;\r\nassert(isequal(y,y_correct))\r\n\r\n%%\r\nx = 62586;\r\ny = closestGeyserPrime(x);\r\ny_correct = 62581;\r\nassert(isequal(y,y_correct))\r\n\r\n%%\r\nx = 103000;\r\ny = closestGeyserPrime(x);\r\ny_correct = 102983;\r\nassert(isequal(y,y_correct))\r\n\r\n%%\r\nx = 203000;\r\ny = closestGeyserPrime(x);\r\ny_correct = 202999;\r\nassert(isequal(y,y_correct))\r\n\r\n%%\r\nx = 465200;\r\ny = closestGeyserPrime(x);\r\ny_correct = 465211;\r\nassert(isequal(y,y_correct))\r\n\r\n%%\r\nx = 888888;\r\ny = closestGeyserPrime(x);\r\ny_correct = 888961;\r\nassert(isequal(y,y_correct))\r\n\r\n%%\r\nx = 1e7;\r\ny = closestGeyserPrime(x);\r\ny_correct = 10000019;\r\nassert(isequal(y,y_correct))\r\n\r\n%%\r\nx = 5e8;\r\ny = closestGeyserPrime(x);\r\ny_correct = 500000003;\r\nassert(isequal(y,y_correct))","published":true,"deleted":false,"likes_count":1,"comments_count":2,"created_by":46909,"edited_by":46909,"edited_at":"2024-08-25T18:02:27.000Z","deleted_by":null,"deleted_at":null,"solvers_count":8,"test_suite_updated_at":null,"rescore_all_solutions":false,"group_id":1,"created_at":"2024-08-24T15:42:12.000Z","updated_at":"2026-04-24T09:48:51.000Z","published_at":"2024-08-24T15:42:42.000Z","restored_at":null,"restored_by":null,"spam":null,"simulink":false,"admin_reviewed":false,"description_opc":"{\"parts\":[{\"partUri\":\"/matlab/document.xml\",\"contentType\":\"application/vnd.mathworks.matlab.code.document+xml\",\"content\":\"\u003c?xml version=\\\"1.0\\\" encoding=\\\"UTF-8\\\"?\u003e\u003cw:document xmlns:w=\\\"http://schemas.openxmlformats.org/wordprocessingml/2006/main\\\"\u003e\u003cw:body\u003e\u003cw:p\u003e\u003cw:pPr\u003e\u003cw:pStyle w:val=\\\"text\\\"/\u003e\u003cw:jc w:val=\\\"left\\\"/\u003e\u003c/w:pPr\u003e\u003cw:r\u003e\u003cw:t\u003eMy wife and I celebrated our honeymoon and our recent anniversary in Yellowstone and Grand Teton National Parks. After returning from our latest trip, I made her a word puzzle involving geysers, mud pots, and canyons. Because \u003c/w:t\u003e\u003c/w:r\u003e\u003cw:hyperlink w:docLocation=\\\"https://www.youtube.com/watch?v=p3pI3K6CLSY\\\"\u003e\u003cw:r\u003e\u003cw:t\u003egeysers eject water and gases\u003c/w:t\u003e\u003c/w:r\u003e\u003c/w:hyperlink\u003e\u003cw:r\u003e\u003cw:t\u003e, a geyser in the puzzle was a word that could eject a single letter and become a new word. For example, SHORT could eject H and become SORT. \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\u003eThis problem deals with \u003c/w:t\u003e\u003c/w:r\u003e\u003cw:r\u003e\u003cw:rPr\u003e\u003cw:i/\u003e\u003c/w:rPr\u003e\u003cw:t\u003egeyser primes\u003c/w:t\u003e\u003c/w:r\u003e\u003cw:r\u003e\u003cw:t\u003e, defined as prime numbers that can eject only one of their digits and become new primes. 263 is a geyser prime because it can eject the 6 (and only the 6) and become the prime 23. 10007 is a geyser prime because ejecting the 1 leads to 7 (ignore leading zeros). 251 is not a geyser prime because none of 51, 21, and 25 is prime. 197 is not a geyser prime because it can eject any one of its digits and result in a prime (97, 17, or 19). 233 is not a geyser prime because ejecting either of the 3s results in a prime. Remember that 1 is neither prime nor composite and notice the difference between geyser primes and \u003c/w:t\u003e\u003c/w:r\u003e\u003cw:hyperlink w:docLocation=\\\"https://www.mathworks.com/matlabcentral/cody/problems/47833-list-the-delete-a-digit-primes\\\"\u003e\u003cw:r\u003e\u003cw:rPr\u003e\u003cw:u/\u003e\u003c/w:rPr\u003e\u003cw:t\u003edelete-a-digit primes\u003c/w:t\u003e\u003c/w:r\u003e\u003c/w:hyperlink\u003e\u003cw:r\u003e\u003cw:t\u003e. \u003c/w:t\u003e\u003c/w:r\u003e\u003c/w:p\u003e\u003cw:p\u003e\u003cw:pPr\u003e\u003cw:pStyle w:val=\\\"text\\\"/\u003e\u003cw:jc w:val=\\\"left\\\"/\u003e\u003c/w:pPr\u003e\u003cw:r\u003e\u003cw:t\u003eWrite a function that produces the geyser prime closest to the input number. If two numbers are equally distant from the input, choose the smaller. \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":60760,"title":"Find the closest canyon prime","description":"My wife and I celebrated our honeymoon and most recent anniversary in Yellowstone and Grand Teton National Parks. After returning from our latest trip, I made her a word puzzle involving geysers, mud pots, and canyons. Because canyons form when rock erodes and walls remain, a canyon in the puzzle was a word that could erode two or more letters from the interior to form a new word, leaving at least one of the original letters on each side. For example, if TOPLAS is eroded from PROTOPLASM, then PROM is formed.\r\nThis problem deals with canyon primes, defined as a prime number that can erode two or more consecutive interior digits, leaving at least one original digit on each side, and become a new prime. 4813 and 4817 are both canyon primes because eroding 81 from both leaves 43 and 47, which are prime. 29411 is a canyon prime because eroding 94 leaves 211, which is prime. 299623 is a canyon prime because eroding 996 leaves 223, which is prime.\r\nWrite a function that produces the canyon prime closest to the input number. If two numbers are equally distant from the input, choose the smaller.","description_html":"\u003cdiv style = \"text-align: start; line-height: 20.44px; min-height: 0px; white-space: normal; color: rgb(0, 0, 0); font-family: Menlo, Monaco, Consolas, monospace; font-style: normal; font-size: 14px; font-weight: 400; text-decoration: none solid rgb(0, 0, 0); white-space: normal; \"\u003e\u003cdiv style=\"block-size: 249px; display: block; min-width: 0px; padding-block-start: 0px; padding-top: 0px; perspective-origin: 407px 124.5px; transform-origin: 407px 124.5px; vertical-align: baseline; \"\u003e\u003cdiv style=\"block-size: 105px; font-family: Helvetica, Arial, sans-serif; line-height: 21px; margin-block-end: 9px; margin-block-start: 2px; margin-bottom: 9px; margin-inline-end: 10px; margin-inline-start: 4px; margin-left: 4px; margin-right: 10px; margin-top: 2px; perspective-origin: 384px 52.5px; text-align: left; transform-origin: 384px 52.5px; white-space-collapse: preserve; margin-left: 4px; margin-top: 2px; margin-bottom: 9px; margin-right: 10px; \"\u003e\u003cspan style=\"block-size: auto; display: inline; margin-block-end: 0px; margin-block-start: 0px; margin-bottom: 0px; margin-inline-end: 0px; margin-inline-start: 0px; margin-left: 0px; margin-right: 0px; margin-top: 0px; perspective-origin: 0px 0px; transform-origin: 0px 0px; unicode-bidi: normal; \"\u003e\u003cspan style=\"\"\u003eMy wife and I celebrated our honeymoon and most recent anniversary in Yellowstone and Grand Teton National Parks. After returning from our latest trip, I made her a word puzzle involving geysers, mud pots, and canyons. Because canyons form when rock erodes and walls remain, a canyon in the puzzle was a word that could erode two or more letters from the interior to form a new word, leaving at least one of the original letters on each side. For example, if TOPLAS is eroded from PROTOPLASM, then PROM is formed.\u003c/span\u003e\u003c/span\u003e\u003c/div\u003e\u003cdiv style=\"block-size: 84px; font-family: Helvetica, Arial, sans-serif; line-height: 21px; margin-block-end: 9px; margin-block-start: 2px; margin-bottom: 9px; margin-inline-end: 10px; margin-inline-start: 4px; margin-left: 4px; margin-right: 10px; margin-top: 2px; perspective-origin: 384px 42px; text-align: left; transform-origin: 384px 42px; white-space-collapse: preserve; margin-left: 4px; margin-top: 2px; margin-bottom: 9px; margin-right: 10px; \"\u003e\u003cspan style=\"block-size: auto; display: inline; margin-block-end: 0px; margin-block-start: 0px; margin-bottom: 0px; margin-inline-end: 0px; margin-inline-start: 0px; margin-left: 0px; margin-right: 0px; margin-top: 0px; perspective-origin: 0px 0px; transform-origin: 0px 0px; unicode-bidi: normal; \"\u003e\u003cspan style=\"\"\u003eThis problem deals with \u003c/span\u003e\u003c/span\u003e\u003cspan style=\"block-size: auto; display: inline; margin-block-end: 0px; margin-block-start: 0px; margin-bottom: 0px; margin-inline-end: 0px; margin-inline-start: 0px; margin-left: 0px; margin-right: 0px; margin-top: 0px; perspective-origin: 0px 0px; transform-origin: 0px 0px; unicode-bidi: normal; \"\u003e\u003cspan style=\"font-style: italic; \"\u003ecanyon primes\u003c/span\u003e\u003c/span\u003e\u003cspan style=\"block-size: auto; display: inline; margin-block-end: 0px; margin-block-start: 0px; margin-bottom: 0px; margin-inline-end: 0px; margin-inline-start: 0px; margin-left: 0px; margin-right: 0px; margin-top: 0px; perspective-origin: 0px 0px; transform-origin: 0px 0px; unicode-bidi: normal; \"\u003e\u003cspan style=\"\"\u003e, defined as a prime number that can erode two or more consecutive interior digits, leaving at least one original digit on each side, and become a new prime. 4813 and 4817 are both canyon primes because eroding 81 from both leaves 43 and 47, which are prime. 29411 is a canyon prime because eroding 94 leaves 211, which is prime. 299623 is a canyon prime because eroding 996 leaves 223, which is prime.\u003c/span\u003e\u003c/span\u003e\u003c/div\u003e\u003cdiv style=\"block-size: 42px; font-family: Helvetica, Arial, sans-serif; line-height: 21px; margin-block-end: 9px; margin-block-start: 2px; margin-bottom: 9px; margin-inline-end: 10px; margin-inline-start: 4px; margin-left: 4px; margin-right: 10px; margin-top: 2px; perspective-origin: 384px 21px; text-align: left; transform-origin: 384px 21px; white-space-collapse: preserve; margin-left: 4px; margin-top: 2px; margin-bottom: 9px; margin-right: 10px; \"\u003e\u003cspan style=\"block-size: auto; display: inline; margin-block-end: 0px; margin-block-start: 0px; margin-bottom: 0px; margin-inline-end: 0px; margin-inline-start: 0px; margin-left: 0px; margin-right: 0px; margin-top: 0px; perspective-origin: 0px 0px; transform-origin: 0px 0px; unicode-bidi: normal; \"\u003e\u003cspan style=\"\"\u003eWrite a function that produces the canyon prime closest to the input number. If two numbers are equally distant from the input, choose the smaller.\u003c/span\u003e\u003c/span\u003e\u003c/div\u003e\u003c/div\u003e\u003c/div\u003e","function_template":"function y = closestCanyonPrime(x)\r\n  y = min(dist(x-primes(x)));\r\nend","test_suite":"%%\r\nx = 1:1011;\r\ny = arrayfun(@closestCanyonPrime,x);\r\nassert(all(y==1009))\r\n\r\n%%\r\nx = 1500;\r\ny = closestCanyonPrime(x);\r\ny_correct = 1499;\r\nassert(isequal(y,y_correct))\r\n\r\n%%\r\nx = 4513;\r\ny = closestCanyonPrime(x);\r\ny_correct = 4513;\r\nassert(isequal(y,y_correct))\r\n\r\n%%\r\nx = 8300;\r\ny = closestCanyonPrime(x);\r\ny_correct = 8293;\r\nassert(isequal(y,y_correct))\r\n\r\n%%\r\nx = 62586;\r\ny = closestCanyonPrime(x);\r\ny_correct = 62581;\r\nassert(isequal(y,y_correct))\r\n\r\n%%\r\nx = 99849;\r\ny = closestCanyonPrime(x);\r\ny_correct = 99829;\r\nassert(isequal(y,y_correct))\r\n\r\n%%\r\nx = 103000;\r\ny = closestCanyonPrime(x);\r\ny_correct = 103001;\r\nassert(isequal(y,y_correct))\r\n\r\n%%\r\nx = 203000;\r\ny = closestCanyonPrime(x);\r\ny_correct = 202999;\r\nassert(isequal(y,y_correct))\r\n\r\n%%\r\nx = 465200;\r\ny = closestCanyonPrime(x);\r\ny_correct = 465209;\r\nassert(isequal(y,y_correct))\r\n\r\n%%\r\nx = 888888;\r\ny = closestCanyonPrime(x);\r\ny_correct = 888887;\r\nassert(isequal(y,y_correct))\r\n\r\n%%\r\nx = 1e7;\r\ny = closestCanyonPrime(x);\r\ny_correct = 9999991;\r\nassert(isequal(y,y_correct))\r\n\r\n%%\r\nx = 5e8;\r\ny = closestCanyonPrime(x);\r\ny_correct = 500000003;\r\nassert(isequal(y,y_correct))","published":true,"deleted":false,"likes_count":0,"comments_count":3,"created_by":46909,"edited_by":46909,"edited_at":"2024-11-22T14:28:24.000Z","deleted_by":null,"deleted_at":null,"solvers_count":5,"test_suite_updated_at":null,"rescore_all_solutions":false,"group_id":1,"created_at":"2024-11-11T04:30:55.000Z","updated_at":"2025-07-23T20:49:51.000Z","published_at":"2024-11-11T04:31:10.000Z","restored_at":null,"restored_by":null,"spam":null,"simulink":false,"admin_reviewed":false,"description_opc":"{\"parts\":[{\"partUri\":\"/matlab/document.xml\",\"contentType\":\"application/vnd.mathworks.matlab.code.document+xml\",\"content\":\"\u003c?xml version=\\\"1.0\\\" encoding=\\\"UTF-8\\\"?\u003e\u003cw:document xmlns:w=\\\"http://schemas.openxmlformats.org/wordprocessingml/2006/main\\\"\u003e\u003cw:body\u003e\u003cw:p\u003e\u003cw:pPr\u003e\u003cw:pStyle w:val=\\\"text\\\"/\u003e\u003cw:jc w:val=\\\"left\\\"/\u003e\u003c/w:pPr\u003e\u003cw:r\u003e\u003cw:t\u003eMy wife and I celebrated our honeymoon and most recent anniversary in Yellowstone and Grand Teton National Parks. After returning from our latest trip, I made her a word puzzle involving geysers, mud pots, and canyons. Because canyons form when rock erodes and walls remain, a canyon in the puzzle was a word that could erode two or more letters from the interior to form a new word, leaving at least one of the original letters on each side. For example, if TOPLAS is eroded from PROTOPLASM, then PROM is formed.\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\u003eThis problem deals with \u003c/w:t\u003e\u003c/w:r\u003e\u003cw:r\u003e\u003cw:rPr\u003e\u003cw:i/\u003e\u003c/w:rPr\u003e\u003cw:t\u003ecanyon primes\u003c/w:t\u003e\u003c/w:r\u003e\u003cw:r\u003e\u003cw:t\u003e, defined as a prime number that can erode two or more consecutive interior digits, leaving at least one original digit on each side, and become a new prime. 4813 and 4817 are both canyon primes because eroding 81 from both leaves 43 and 47, which are prime. 29411 is a canyon prime because eroding 94 leaves 211, which is prime. 299623 is a canyon prime because eroding 996 leaves 223, which is prime.\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\u003eWrite a function that produces the canyon prime closest to the input number. If two numbers are equally distant from the input, choose the smaller.\u003c/w:t\u003e\u003c/w:r\u003e\u003c/w:p\u003e\u003c/w:body\u003e\u003c/w:document\u003e\",\"relationship\":null}],\"relationships\":[{\"relationshipType\":\"http://schemas.mathworks.com/matlab/code/2013/relationships/document\",\"target\":\"/matlab/document.xml\",\"relationshipId\":\"rId1\"}]}"},{"id":60733,"title":"Find the closest geyser prime","description":"My wife and I celebrated our honeymoon and our recent anniversary in Yellowstone and Grand Teton National Parks. After returning from our latest trip, I made her a word puzzle involving geysers, mud pots, and canyons. Because geysers eject water and gases, a geyser in the puzzle was a word that could eject a single letter and become a new word. For example, SHORT could eject H and become SORT. \r\nThis problem deals with geyser primes, defined as prime numbers that can eject only one of their digits and become new primes. 263 is a geyser prime because it can eject the 6 (and only the 6) and become the prime 23. 10007 is a geyser prime because ejecting the 1 leads to 7 (ignore leading zeros). 251 is not a geyser prime because none of 51, 21, and 25 is prime. 197 is not a geyser prime because it can eject any one of its digits and result in a prime (97, 17, or 19). 233 is not a geyser prime because ejecting either of the 3s results in a prime. Remember that 1 is neither prime nor composite and notice the difference between geyser primes and delete-a-digit primes. \r\nWrite a function that produces the geyser prime closest to the input number. If two numbers are equally distant from the input, choose the smaller. ","description_html":"\u003cdiv style = \"text-align: start; line-height: 20.44px; min-height: 0px; white-space: normal; color: rgb(0, 0, 0); font-family: Menlo, Monaco, Consolas, monospace; font-style: normal; font-size: 14px; font-weight: 400; text-decoration: none solid rgb(0, 0, 0); white-space: normal; \"\u003e\u003cdiv style=\"block-size: 270px; display: block; min-width: 0px; padding-block-start: 0px; padding-top: 0px; perspective-origin: 407px 135px; transform-origin: 407px 135px; vertical-align: baseline; \"\u003e\u003cdiv style=\"block-size: 84px; font-family: Helvetica, Arial, sans-serif; line-height: 21px; margin-block-end: 9px; margin-block-start: 2px; margin-bottom: 9px; margin-inline-end: 10px; margin-inline-start: 4px; margin-left: 4px; margin-right: 10px; margin-top: 2px; perspective-origin: 384px 42px; text-align: left; transform-origin: 384px 42px; white-space-collapse: preserve; margin-left: 4px; margin-top: 2px; margin-bottom: 9px; margin-right: 10px; \"\u003e\u003cspan style=\"block-size: auto; display: inline; margin-block-end: 0px; margin-block-start: 0px; margin-bottom: 0px; margin-inline-end: 0px; margin-inline-start: 0px; margin-left: 0px; margin-right: 0px; margin-top: 0px; perspective-origin: 0px 0px; transform-origin: 0px 0px; unicode-bidi: normal; \"\u003e\u003cspan style=\"\"\u003eMy wife and I celebrated our honeymoon and our recent anniversary in Yellowstone and Grand Teton National Parks. After returning from our latest trip, I made her a word puzzle involving geysers, mud pots, and canyons. Because \u003c/span\u003e\u003c/span\u003e\u003ca target='_blank' href = \"https://www.youtube.com/watch?v=p3pI3K6CLSY\"\u003e\u003cspan style=\"\"\u003e\u003cspan style=\"\"\u003egeysers eject water and gases\u003c/span\u003e\u003c/span\u003e\u003c/a\u003e\u003cspan style=\"block-size: auto; display: inline; margin-block-end: 0px; margin-block-start: 0px; margin-bottom: 0px; margin-inline-end: 0px; margin-inline-start: 0px; margin-left: 0px; margin-right: 0px; margin-top: 0px; perspective-origin: 0px 0px; transform-origin: 0px 0px; unicode-bidi: normal; \"\u003e\u003cspan style=\"\"\u003e, a geyser in the puzzle was a word that could eject a single letter and become a new word. For example, SHORT could eject H and become SORT. \u003c/span\u003e\u003c/span\u003e\u003c/div\u003e\u003cdiv style=\"block-size: 126px; font-family: Helvetica, Arial, sans-serif; line-height: 21px; margin-block-end: 9px; margin-block-start: 2px; margin-bottom: 9px; margin-inline-end: 10px; margin-inline-start: 4px; margin-left: 4px; margin-right: 10px; margin-top: 2px; perspective-origin: 384px 63px; text-align: left; transform-origin: 384px 63px; white-space-collapse: preserve; margin-left: 4px; margin-top: 2px; margin-bottom: 9px; margin-right: 10px; \"\u003e\u003cspan style=\"block-size: auto; display: inline; margin-block-end: 0px; margin-block-start: 0px; margin-bottom: 0px; margin-inline-end: 0px; margin-inline-start: 0px; margin-left: 0px; margin-right: 0px; margin-top: 0px; perspective-origin: 0px 0px; transform-origin: 0px 0px; unicode-bidi: normal; \"\u003e\u003cspan style=\"\"\u003eThis problem deals with \u003c/span\u003e\u003c/span\u003e\u003cspan style=\"block-size: auto; display: inline; margin-block-end: 0px; margin-block-start: 0px; margin-bottom: 0px; margin-inline-end: 0px; margin-inline-start: 0px; margin-left: 0px; margin-right: 0px; margin-top: 0px; perspective-origin: 0px 0px; transform-origin: 0px 0px; unicode-bidi: normal; \"\u003e\u003cspan style=\"font-style: italic; \"\u003egeyser primes\u003c/span\u003e\u003c/span\u003e\u003cspan style=\"block-size: auto; display: inline; margin-block-end: 0px; margin-block-start: 0px; margin-bottom: 0px; margin-inline-end: 0px; margin-inline-start: 0px; margin-left: 0px; margin-right: 0px; margin-top: 0px; perspective-origin: 0px 0px; transform-origin: 0px 0px; unicode-bidi: normal; \"\u003e\u003cspan style=\"\"\u003e, defined as prime numbers that can eject only one of their digits and become new primes. 263 is a geyser prime because it can eject the 6 (and only the 6) and become the prime 23. 10007 is a geyser prime because ejecting the 1 leads to 7 (ignore leading zeros). 251 is not a geyser prime because none of 51, 21, and 25 is prime. 197 is not a geyser prime because it can eject any one of its digits and result in a prime (97, 17, or 19). 233 is not a geyser prime because ejecting either of the 3s results in a prime. Remember that 1 is neither prime nor composite and notice the difference between geyser primes and \u003c/span\u003e\u003c/span\u003e\u003ca target='_blank' href = \"https://www.mathworks.com/matlabcentral/cody/problems/47833-list-the-delete-a-digit-primes\"\u003e\u003cspan style=\"\"\u003e\u003cspan style=\"text-decoration: underline; text-decoration-line: underline; \"\u003edelete-a-digit primes\u003c/span\u003e\u003c/span\u003e\u003c/a\u003e\u003cspan style=\"block-size: auto; display: inline; margin-block-end: 0px; margin-block-start: 0px; margin-bottom: 0px; margin-inline-end: 0px; margin-inline-start: 0px; margin-left: 0px; margin-right: 0px; margin-top: 0px; perspective-origin: 0px 0px; transform-origin: 0px 0px; unicode-bidi: normal; \"\u003e\u003cspan style=\"\"\u003e. \u003c/span\u003e\u003c/span\u003e\u003c/div\u003e\u003cdiv style=\"block-size: 42px; font-family: Helvetica, Arial, sans-serif; line-height: 21px; margin-block-end: 9px; margin-block-start: 2px; margin-bottom: 9px; margin-inline-end: 10px; margin-inline-start: 4px; margin-left: 4px; margin-right: 10px; margin-top: 2px; perspective-origin: 384px 21px; text-align: left; transform-origin: 384px 21px; white-space-collapse: preserve; margin-left: 4px; margin-top: 2px; margin-bottom: 9px; margin-right: 10px; \"\u003e\u003cspan style=\"block-size: auto; display: inline; margin-block-end: 0px; margin-block-start: 0px; margin-bottom: 0px; margin-inline-end: 0px; margin-inline-start: 0px; margin-left: 0px; margin-right: 0px; margin-top: 0px; perspective-origin: 0px 0px; transform-origin: 0px 0px; unicode-bidi: normal; \"\u003e\u003cspan style=\"\"\u003eWrite a function that produces the geyser prime closest to the input number. If two numbers are equally distant from the input, choose the smaller. \u003c/span\u003e\u003c/span\u003e\u003c/div\u003e\u003c/div\u003e\u003c/div\u003e","function_template":"function y = closestGeyserPrime(x)\r\n  y = min(abs(primes(x)-x));\r\nend","test_suite":"%%\r\nx = 1:15;\r\ny = arrayfun(@closestGeyserPrime,x);\r\nassert(all(y==13))\r\n\r\n%%\r\nx = 45;\r\ny = closestGeyserPrime(x);\r\ny_correct = 43;\r\nassert(isequal(y,y_correct))\r\n\r\n%%\r\nx = 197;\r\ny = closestGeyserPrime(x);\r\ny_correct = 211;\r\nassert(isequal(y,y_correct))\r\n\r\n%%\r\nx = 233;\r\ny = closestGeyserPrime(x);\r\ny_correct = 241;\r\nassert(isequal(y,y_correct))\r\n\r\n%%\r\nx = 251;\r\ny = closestGeyserPrime(x);\r\ny_correct = 241;\r\nassert(isequal(y,y_correct))\r\n\r\n%%\r\nx = 260;\r\ny = closestGeyserPrime(x);\r\ny_correct = 263;\r\nassert(isequal(y,y_correct))\r\n\r\n%%\r\nx = 586;\r\ny = closestGeyserPrime(x);\r\ny_correct = 571;\r\nassert(isequal(y,y_correct))\r\n\r\n%%\r\nx = 587;\r\ny = closestGeyserPrime(x);\r\ny_correct = 601;\r\nassert(isequal(y,y_correct))\r\n\r\n%%\r\nx = 1500;\r\ny = closestGeyserPrime(x);\r\ny_correct = 1489;\r\nassert(isequal(y,y_correct))\r\n\r\n%%\r\nx = 4511;\r\ny = closestGeyserPrime(x);\r\ny_correct = 4507;\r\nassert(isequal(y,y_correct))\r\n\r\n%%\r\nx = 8300;\r\ny = closestGeyserPrime(x);\r\ny_correct = 8317;\r\nassert(isequal(y,y_correct))\r\n\r\n%%\r\nx = 62586;\r\ny = closestGeyserPrime(x);\r\ny_correct = 62581;\r\nassert(isequal(y,y_correct))\r\n\r\n%%\r\nx = 103000;\r\ny = closestGeyserPrime(x);\r\ny_correct = 102983;\r\nassert(isequal(y,y_correct))\r\n\r\n%%\r\nx = 203000;\r\ny = closestGeyserPrime(x);\r\ny_correct = 202999;\r\nassert(isequal(y,y_correct))\r\n\r\n%%\r\nx = 465200;\r\ny = closestGeyserPrime(x);\r\ny_correct = 465211;\r\nassert(isequal(y,y_correct))\r\n\r\n%%\r\nx = 888888;\r\ny = closestGeyserPrime(x);\r\ny_correct = 888961;\r\nassert(isequal(y,y_correct))\r\n\r\n%%\r\nx = 1e7;\r\ny = closestGeyserPrime(x);\r\ny_correct = 10000019;\r\nassert(isequal(y,y_correct))\r\n\r\n%%\r\nx = 5e8;\r\ny = closestGeyserPrime(x);\r\ny_correct = 500000003;\r\nassert(isequal(y,y_correct))","published":true,"deleted":false,"likes_count":1,"comments_count":2,"created_by":46909,"edited_by":46909,"edited_at":"2024-08-25T18:02:27.000Z","deleted_by":null,"deleted_at":null,"solvers_count":8,"test_suite_updated_at":null,"rescore_all_solutions":false,"group_id":1,"created_at":"2024-08-24T15:42:12.000Z","updated_at":"2026-04-24T09:48:51.000Z","published_at":"2024-08-24T15:42:42.000Z","restored_at":null,"restored_by":null,"spam":null,"simulink":false,"admin_reviewed":false,"description_opc":"{\"parts\":[{\"partUri\":\"/matlab/document.xml\",\"contentType\":\"application/vnd.mathworks.matlab.code.document+xml\",\"content\":\"\u003c?xml version=\\\"1.0\\\" encoding=\\\"UTF-8\\\"?\u003e\u003cw:document xmlns:w=\\\"http://schemas.openxmlformats.org/wordprocessingml/2006/main\\\"\u003e\u003cw:body\u003e\u003cw:p\u003e\u003cw:pPr\u003e\u003cw:pStyle w:val=\\\"text\\\"/\u003e\u003cw:jc w:val=\\\"left\\\"/\u003e\u003c/w:pPr\u003e\u003cw:r\u003e\u003cw:t\u003eMy wife and I celebrated our honeymoon and our recent anniversary in Yellowstone and Grand Teton National Parks. After returning from our latest trip, I made her a word puzzle involving geysers, mud pots, and canyons. Because \u003c/w:t\u003e\u003c/w:r\u003e\u003cw:hyperlink w:docLocation=\\\"https://www.youtube.com/watch?v=p3pI3K6CLSY\\\"\u003e\u003cw:r\u003e\u003cw:t\u003egeysers eject water and gases\u003c/w:t\u003e\u003c/w:r\u003e\u003c/w:hyperlink\u003e\u003cw:r\u003e\u003cw:t\u003e, a geyser in the puzzle was a word that could eject a single letter and become a new word. For example, SHORT could eject H and become SORT. \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\u003eThis problem deals with \u003c/w:t\u003e\u003c/w:r\u003e\u003cw:r\u003e\u003cw:rPr\u003e\u003cw:i/\u003e\u003c/w:rPr\u003e\u003cw:t\u003egeyser primes\u003c/w:t\u003e\u003c/w:r\u003e\u003cw:r\u003e\u003cw:t\u003e, defined as prime numbers that can eject only one of their digits and become new primes. 263 is a geyser prime because it can eject the 6 (and only the 6) and become the prime 23. 10007 is a geyser prime because ejecting the 1 leads to 7 (ignore leading zeros). 251 is not a geyser prime because none of 51, 21, and 25 is prime. 197 is not a geyser prime because it can eject any one of its digits and result in a prime (97, 17, or 19). 233 is not a geyser prime because ejecting either of the 3s results in a prime. Remember that 1 is neither prime nor composite and notice the difference between geyser primes and \u003c/w:t\u003e\u003c/w:r\u003e\u003cw:hyperlink w:docLocation=\\\"https://www.mathworks.com/matlabcentral/cody/problems/47833-list-the-delete-a-digit-primes\\\"\u003e\u003cw:r\u003e\u003cw:rPr\u003e\u003cw:u/\u003e\u003c/w:rPr\u003e\u003cw:t\u003edelete-a-digit primes\u003c/w:t\u003e\u003c/w:r\u003e\u003c/w:hyperlink\u003e\u003cw:r\u003e\u003cw:t\u003e. \u003c/w:t\u003e\u003c/w:r\u003e\u003c/w:p\u003e\u003cw:p\u003e\u003cw:pPr\u003e\u003cw:pStyle w:val=\\\"text\\\"/\u003e\u003cw:jc w:val=\\\"left\\\"/\u003e\u003c/w:pPr\u003e\u003cw:r\u003e\u003cw:t\u003eWrite a function that produces the geyser prime closest to the input number. If two numbers are equally distant from the input, choose the smaller. 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