Cod sursa(job #633877)
Utilizator | Data | 14 noiembrie 2011 23:32:40 | |
---|---|---|---|
Problema | Ciurul lui Eratosthenes | Scor | 60 |
Compilator | cpp | Status | done |
Runda | Arhiva educationala | Marime | 0.34 kb |
// ciurul lui Eratostene
#include <stdio.h>
bool prim[2000000];
int main()
{
long n,i,j,nr=0;
freopen("ciur.in", "r", stdin);
freopen("ciur.out", "w", stdout);
scanf("%d", &n);
for (i=2;i<=n;i++)
{
if (prim[i]==0)
{
nr++;
for (j=i+i;j<=n;j+=i)
prim[j]=1;
}
}
printf("%d\n",nr);
return 0;
}