The 1 millionth fibonacci number

gcc -x c -o /tmp/out - -lgmp <<< '#include <stdlib.h> ... SEE SAMPLE OUTPUT FOR FULL COMMAND
It's hard to beat C. This is just slightly faster than the bc version on my machine. real 0m26.856s user 0m25.030s sys 0m0.024s Requirements: libgmp headers, gcc.
Sample Output
The command is:

gcc -x c -o /tmp/out - -lgmp <<< '#include <stdlib.h> 
#include <stdio.h>
#include <string.h>
#include <stdint.h>
#include <gmp.h>
void omg_i_love_leonardo_of_pisa(uint32_t num, mpz_t * result) { mpz_t retval, last, tmp; mpz_init(retval); mpz_init(last); mpz_init(tmp); uint32_t i = 1; if(num == 0) return; mpz_set_ui(retval, 1U); mpz_set_ui(last, 0U); for(; i < num; i++) { mpz_set(tmp, retval); mpz_add(retval, retval, last); mpz_set(last, tmp); } mpz_set(*result, retval); } int main() { uint32_t num; mpz_t fibo; mpz_init(fibo); omg_i_love_leonardo_of_pisa(1000001, &fibo); mpz_out_str(stdout, 10, fibo); printf("\n"); return 1; }
' && time /tmp/out

-5
By: hank
2009-09-10 02:10:46

What Others Think

Sorry Hank, you're 2 secs slower than the bc version on an atom 1.6Ghzs netbook. :) Nice try though. For the cash prize you need to use commonly available shell tools rather than custom c code (After all, I could probably install mathematica and beat bc!)
Escher · 471 weeks and 5 days ago
Also, ~12 secs slower than bc version on a Core 2 Duo (48 secs v 36 secs)
Escher · 471 weeks and 5 days ago
I voted this down because we're really stretching the limits of what is "command line fu" here. A few more like this and this place loses its charm. I wish people would try and stick to simlpe, short-ish, command lines. Even if the utility used is not a standard or default one (exiftool in one of the other recent posts, for instance), the *command* should be one you wouldn't mind typing or pasting if needed
sitaram · 471 weeks and 3 days ago

What do you think?

Any thoughts on this command? Does it work on your machine? Can you do the same thing with only 14 characters?

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