Cod sursa(job #728040)
Utilizator | Data | 28 martie 2012 14:20:07 | |
---|---|---|---|
Problema | Ciurul lui Eratosthenes | Scor | 20 |
Compilator | cpp | Status | done |
Runda | Arhiva educationala | Marime | 0.4 kb |
#include <fstream>
using namespace std;
int main(){
long n,i,np=0;
char c[2000001];
ifstream f("ciur.in");
ofstream g("ciur.out");
f>>n;
for(i=2;i<=n;i++)
c[i]=1;
for(i=4;i<=n;i=i+2)
c[i]=0;
for(i=6;i<=n;i=i+3)
c[i]=0;
for(i=10;i<=n;i=i+5)
c[i]=0;
for(i=14;i<=n;i=i+7)
c[i]=0;
for(i=2;i<=n;i++)
if(c[i])
np++;
g<<np;
f.close();
g.close();
return 0;}