Cod sursa(job #852039)
Utilizator | Data | 10 ianuarie 2013 19:37:39 | |
---|---|---|---|
Problema | Ciurul lui Eratosthenes | Scor | 0 |
Compilator | cpp | Status | done |
Runda | Arhiva educationala | Marime | 0.28 kb |
#include<fstream>
using namespace std;
ifstream fin("ciur.in");
ofstream fout("ciur.out");
char ciur[2000000];
int main()
{ int N,nrp=0,i,j;
fin>>N;
for(i=2;i<=N/2;i++)
{ if(!ciur[i])
nrp++;
for(j=i+i;j<=N;j+=i)
ciur[j]=1;
}
fout<<nrp;
return 0;
}