Timeline for Invert the bits of a non-negative integer in Common Lisp (SBCL)
Current License: CC BY-SA 3.0
8 events
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| Oct 15, 2017 at 14:01 | comment | added | wvxvw |
(ash 1 (integer-length n)) is the same as (expt 2 (integer-length n)), though SBCL will probably figure this out on its own.
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| Jan 11, 2017 at 14:54 | comment | added | Vatine |
@Renzo In this specific case, you could actually use - instead of logxor, but I'd probably do it with logxor, as it's more clearly bit manipulation.
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| Jan 11, 2017 at 14:53 | comment | added | Vatine |
@GustavBertram For "number of digits of non-negative number", you could use (1+ (floor (log n <base>))) or (ceiling (log (1+ n) <base)), with a slight preference for the latter, as it sanely handles n == 0.
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| Jan 10, 2017 at 14:11 | vote | accept | Gustav Bertram | ||
| Jan 10, 2017 at 14:11 | comment | added | Gustav Bertram |
Oh man, I had gotten so close to this. I was stuck on (ceiling (log n 2)) instead of integer-length, which obviously fails on some edge cases.
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| Jan 10, 2017 at 14:00 | history | edited | Renzo | CC BY-SA 3.0 |
added 102 characters in body
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| Jan 10, 2017 at 14:00 | comment | added | Rainer Joswig | that's a nice answer | |
| Jan 10, 2017 at 13:56 | history | answered | Renzo | CC BY-SA 3.0 |