Cod sursa(job #447047)
Utilizator | alexandru alexandru92 | Data | 27 aprilie 2010 16:38:16 |
---|---|---|---|
Problema | Ciurul lui Eratosthenes | Scor | 30 |
Compilator | cpp | Status | done |
Runda | Arhiva educationala | Marime | 0.54 kb |
/*
* File: main.cpp
* Author: virtualdemon
*
* Created on April 27, 2010, 4:33 PM
*/
#include <cstdlib>
#include <fstream>
#define Nmax 2000011
/*
*
*/
using namespace std;
char is_prime[Nmax];
int main(int argc, char** argv)
{
int N, nr=0, i, j;
ifstream in( "ciur.in" );
in>>N;
for( i=2; i <= N; ++i )
if( !is_prime[i] )
{
for( j=i*i; j <= N; j+=i )
is_prime[j]=1;
++nr;
}
ofstream out( "ciur.out" );
out<<nr<<'\n';
return (EXIT_SUCCESS);
}