Cod sursa(job #3203864)
Utilizator | Buhai Iulia JulyaBuh | Data | 14 februarie 2024 21:52:38 |
---|---|---|---|
Problema | Ciurul lui Eratosthenes | Scor | 30 |
Compilator | cpp-64 | Status | done |
Runda | Arhiva educationala | Marime | 0.53 kb |
#include <iostream>
#include <fstream>
#include <cmath>
using namespace std;
ifstream fin("ciur.in");
ofstream fout("ciur.out");
#define Nmax 200000
int N[Nmax];
int main(){
int n;
fin>>n;
N[0]=1;
int prim=0;
N[1]=1;
for(int i=2; i<=sqrt(n); i++){
if(N[i]==0){
for(int j=2; j<=n/i; j++){
N[i*j]=1;
}
}
}
for(int i=2; i<=n; i++){
if(N[i]==0){
prim=prim+1;
}
}
fout<<prim;
return 0;
}