18 lines
516 B
Plaintext
18 lines
516 B
Plaintext
(setq Lst
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(make
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(for Y (range 1900 2100)
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(for M (range 1 12)
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(and
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(date Y M 31)
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(= "Friday" (day (date Y M 1)))
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(link (list (get *Mon M) Y)) ) ) ) ) )
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(prinl "There are " (length Lst) " months with five weekends:")
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(mapc println (head 5 Lst))
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(prinl "...")
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(mapc println (tail 5 Lst))
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(prinl)
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(setq Lst (diff (range 1900 2100) (uniq (mapcar cadr Lst))))
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(prinl "There are " (length Lst) " years with no five-weekend months:")
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(println Lst)
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