Contents

#include "prime_factors.h"
#include <math.h>

/**
 * find prime factors: brute force version
 * https://en.wikipedia.org/wiki/Trial_division
 */
size_t find_factors(uint64_t n, uint64_t factors[static MAXFACTORS])
{
   int count = 0;
   while ((n % 2 == 0) && (count < MAXFACTORS)) {
      factors[count++] = 2;
      n /= 2;
   }

   for (uint64_t i = 3; (i <= sqrt(n)) && (count < MAXFACTORS); i += 2) {
      while (n % i == 0) {
         factors[count++] = i;
         n /= i;
      }
   }

   if (n > 2) {
      factors[count++] = n;
   }

   return count;
}

Version data entries

71 entries across 71 versions & 1 rubygems

Version	Path
trackler-2.2.1.180	tracks/c/exercises/prime-factors/src/example.c
trackler-2.2.1.179	tracks/c/exercises/prime-factors/src/example.c
trackler-2.2.1.178	tracks/c/exercises/prime-factors/src/example.c
trackler-2.2.1.177	tracks/c/exercises/prime-factors/src/example.c
trackler-2.2.1.176	tracks/c/exercises/prime-factors/src/example.c
trackler-2.2.1.175	tracks/c/exercises/prime-factors/src/example.c
trackler-2.2.1.174	tracks/c/exercises/prime-factors/src/example.c
trackler-2.2.1.173	tracks/c/exercises/prime-factors/src/example.c
trackler-2.2.1.172	tracks/c/exercises/prime-factors/src/example.c
trackler-2.2.1.171	tracks/c/exercises/prime-factors/src/example.c
trackler-2.2.1.170	tracks/c/exercises/prime-factors/src/example.c
trackler-2.2.1.169	tracks/c/exercises/prime-factors/src/example.c
trackler-2.2.1.167	tracks/c/exercises/prime-factors/src/example.c
trackler-2.2.1.166	tracks/c/exercises/prime-factors/src/example.c
trackler-2.2.1.165	tracks/c/exercises/prime-factors/src/example.c
trackler-2.2.1.164	tracks/c/exercises/prime-factors/src/example.c
trackler-2.2.1.163	tracks/c/exercises/prime-factors/src/example.c
trackler-2.2.1.162	tracks/c/exercises/prime-factors/src/example.c
trackler-2.2.1.161	tracks/c/exercises/prime-factors/src/example.c
trackler-2.2.1.160	tracks/c/exercises/prime-factors/src/example.c