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#include "common.h"
#include <stdlib.h>
// TODO: improve performance! not yet working on 32 bit systems
unsigned int getmod(unsigned long p1)
{
unsigned int mod = 1;
if(p1 < 10)
mod = 10;
else if(p1 < 100)
mod = 100;
else if(p1 < 1000)
mod = 1000;
else if(p1 < 10000)
mod = 10000;
else if(p1 < 100000)
mod = 100000;
else if(p1 < 1000000)
mod = 1000000;
else
mod = 0; // should not occur and therefore result in division by zero
return mod;
}
unsigned long findn(unsigned long p1, unsigned long p2)
{
unsigned int mod = getmod(p1);
unsigned long n = mod + p1;
while(n % p2 != 0)
n += mod;
return n;
}
int main(void)
{
unsigned long* p = primes(1000020);
unsigned long pcount = p[0];
unsigned long p1, p2, pos;
unsigned long long result = 0;
for(pos=3; p[pos]<=1000000; pos++)
{
p1 = p[pos];
p2 = p[pos+1];
if(pos%1000==0)
printf("p1: %li\n", p1);
result += findn(p1, p2);
}
printf("%li\n", result);
free(p);
return 0;
}
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