Cod sursa(job #3038430)
Utilizator | Data | 27 martie 2023 13:02:25 | |
---|---|---|---|
Problema | Ciurul lui Eratosthenes | Scor | 100 |
Compilator | cpp-64 | Status | done |
Runda | Arhiva educationala | Marime | 0.45 kb |
#include <fstream>
#include <bitset>
using namespace std;
ifstream cin("ciur.in");
ofstream cout("ciur.out");
bitset<2000001> ciur;
int n;
int nr=0;
void eratostene()
{
ciur[0]=1;
ciur[1]=1;
nr++;
for(int i=3;i<=n;i=i+2)
if(ciur[i]==0)
{
for(int j=i+i;j<=n;j=j+i)
ciur[j]=1;
nr++;
}
}
int main()
{
cin>>n;
eratostene();
cout<<nr;
return 0;
}