Cod sursa(job #1365974)
Utilizator | Data | 28 februarie 2015 17:25:16 | |
---|---|---|---|
Problema | Ciurul lui Eratosthenes | Scor | 0 |
Compilator | cpp | Status | done |
Runda | Arhiva educationala | Marime | 0.4 kb |
#include<fstream>
using namespace std;
bool ciur[2000000];
ifstream in("ciur.in");
ofstream out("ciur.out");
int main()
{
long long d,N,i,nr=0;
in>>N;
for(i=2;i<=N;i++)
{i=i+1;
ciur[i]=0;}
for ( d = 2; d * d < N; d++ )
{if ( ciur[d] == 0 )
{for ( i = d * d; i < N; i = i + d )
{
ciur[i] = 1;
nr++;}}
}
out<<nr;
return 0;
}