Cod sursa(job #1363284)
Utilizator | Data | 26 februarie 2015 20:58:12 | |
---|---|---|---|
Problema | Ciurul lui Eratosthenes | Scor | 30 |
Compilator | cpp | Status | done |
Runda | Arhiva educationala | Marime | 0.41 kb |
#include<stdio.h>
bool a[2000002];
int main()
{
FILE *fin,*fout;
fin=fopen("ciur.in","r");
fout=fopen("ciur.out","w");
int n,c=1;
fscanf(fin,"%d",&n);
for(int i=3;i<=n;i+=2)
{
if(a[i]==0)
{
c++;
for(int j=i;j*i<=n;j+=2)
{
a[i*j]=1;
}
}
}
fprintf(fout,"%d",c);
}