Cod sursa(job #1351553)
Utilizator | Data | 21 februarie 2015 11:12:10 | |
---|---|---|---|
Problema | Ciurul lui Eratosthenes | Scor | 100 |
Compilator | cpp | Status | done |
Runda | Arhiva educationala | Marime | 0.41 kb |
#include <iostream>
#include <fstream>
using namespace std;
ifstream fi("ciur.in");
ofstream fo("ciur.out");
bool c[2000001];
int main()
{
int i,j,n,s=0;
fi>>n;
fi.close();
for(i=2;i*i<=n;i++)
if(!c[i])
for(j=i*i;j<=n;j+=i)
c[j]=1;
for(i=2;i<=n;i++)
if(c[i]==0)
s++;
fo<<s;
fo.close();
return 0;
}