Cod sursa(job #500002)
Utilizator | Data | 11 noiembrie 2010 10:26:11 | |
---|---|---|---|
Problema | Ciurul lui Eratosthenes | Scor | 100 |
Compilator | cpp | Status | done |
Runda | Arhiva educationala | Marime | 0.3 kb |
#include<fstream>
using namespace std;
int n,nr,i,j;
char v[2000005];
int main(){
ifstream in("ciur.in");
ofstream out("ciur.out");
in>>n;
for(i=2; i<=n; i++){
v[i]=1;
}
for(i=2,nr=0;i<=n;i++){
if (v[i]){
nr++;
for(j=i+i; j<=n; j+=i){
v[j]=0;}
}
}
out<<nr;
return 0;
}