Cod sursa(job #402400)
Utilizator | Data | 23 februarie 2010 20:39:56 | |
---|---|---|---|
Problema | Ciurul lui Eratosthenes | Scor | 100 |
Compilator | cpp | Status | done |
Runda | Arhiva educationala | Marime | 0.31 kb |
#include<stdio.h>
long nr,n;
char v[2000005];
int main()
{long i,j;
freopen("ciur.in","r",stdin);
freopen("ciur.out","w",stdout);
scanf("%ld",&n);
v[2]=1;nr=1;
for(i=3;i<=n;i+=2)
v[i]=1;
for(i=3;i<=n;i+=2)
if(v[i])
{nr++;
for(j=i+i;j<=n;j=j+i)
v[j]=0;
}
printf("%ld",nr);
return 0;
}