Cod sursa(job #261894)
Utilizator | Mihai-Alexandru Dusmanu dushmi | Data | 18 februarie 2009 20:44:45 |
---|---|---|---|
Problema | Ciurul lui Eratosthenes | Scor | 100 |
Compilator | cpp | Status | done |
Runda | Arhiva educationala | Marime | 0.46 kb |
#include<stdio.h>
#define NM 2000000
int main()
{
char v[NM+1]={0};
int i,j,n,p;
freopen("ciur.in","r",stdin);
freopen("ciur.out","w",stdout);
scanf("%d",&n);
v[1]=1;
for(i=2;i<=n/2;i++)
if(v[i]==0)
for(j=2;j*i<=n;j++)
v[i*j]=1;
p=0;
for(i=1;i<=n;i++) if(v[i]==0) p++;
printf("%d",p);
return 0;
}