Cod sursa(job #2780897)
Utilizator | Data | 8 octombrie 2021 09:35:26 | |
---|---|---|---|
Problema | Ciurul lui Eratosthenes | Scor | 30 |
Compilator | cpp-64 | Status | done |
Runda | Arhiva educationala | Marime | 0.38 kb |
#include <fstream>
using namespace std;
ifstream cin("ciur.in");
ofstream cout("ciur.out");
int f[2000001], n, i, j, nr;
int main(){
cin>>n;
f[0]=f[1]=1;
for(i=2;i<=n;i++){
if(f[i]==0){
for(j=i*i;j<=n;j+=i)
f[j]=1;
}
}
for(i=2;i<=n;i++){
if(f[i]==0)
nr++;
}
cout<<nr;
}