Cod sursa(job #524034)
Utilizator | Data | 19 ianuarie 2011 22:58:39 | |
---|---|---|---|
Problema | Ciurul lui Eratosthenes | Scor | 100 |
Compilator | cpp | Status | done |
Runda | Arhiva educationala | Marime | 0.21 kb |
#include<fstream.h>
ifstream fin("ciur.in");
ofstream fout("ciur.out");
int n,i,j,nr;
bool p[2000011];
int main()
{ fin>>n;
for(i=2; i<=n; i++)
if(!p[i])
{ nr++; for(j=i+i; j<=n; j+=i) p[j]=1;}
fout<<nr<<'\n';
}