67 lines
1.1 KiB
C
67 lines
1.1 KiB
C
#include <stdio.h>
|
|
#include <stdlib.h>
|
|
#include <math.h>
|
|
#include <time.h>
|
|
#include <gmp.h>
|
|
|
|
int main(int argc, char **argv)
|
|
{
|
|
int i, j, n, max = 0, max_n = 0;
|
|
double elapsed;
|
|
struct timespec start, end;
|
|
mpz_t k, div;
|
|
|
|
clock_gettime(CLOCK_MONOTONIC, &start);
|
|
|
|
mpz_init(k);
|
|
mpz_init(div);
|
|
|
|
for(i = 2; i < 1000; i++)
|
|
{
|
|
j = i;
|
|
|
|
while(j % 2 == 0 && j > 1)
|
|
j /= 2;
|
|
|
|
while(j % 5 == 0 && j > 1)
|
|
j /= 5;
|
|
|
|
mpz_set_ui(k, 9);
|
|
|
|
if(j == 1)
|
|
n = 0;
|
|
else
|
|
{
|
|
n = 1;
|
|
|
|
mpz_set_ui(div, j);
|
|
|
|
while(!mpz_divisible_p(k, div))
|
|
{
|
|
n++;
|
|
mpz_mul_ui(k, k, 10);
|
|
mpz_add_ui(k, k, 9);
|
|
}
|
|
|
|
if(n > max)
|
|
{
|
|
max = n;
|
|
max_n = i;
|
|
}
|
|
}
|
|
}
|
|
|
|
mpz_clears(k, div, NULL);
|
|
|
|
clock_gettime(CLOCK_MONOTONIC, &end);
|
|
|
|
elapsed=(end.tv_sec-start.tv_sec)+(double)(end.tv_nsec-start.tv_nsec)/1000000000;
|
|
|
|
printf("Project Euler, Problem 26\n");
|
|
printf("Answer: %d\n", max_n);
|
|
|
|
printf("Elapsed time: %.9lf seconds\n", elapsed);
|
|
|
|
return 0;
|
|
}
|