Cod sursa(job #3141336)
Utilizator | Data | 13 iulie 2023 17:56:11 | |
---|---|---|---|
Problema | Ciurul lui Eratosthenes | Scor | 40 |
Compilator | cpp-64 | Status | done |
Runda | Arhiva educationala | Marime | 0.59 kb |
#include <bits/stdc++.h>
using namespace std;
ifstream fin ("ciur.in");
ofstream fout ("ciur.out");
int IsPrime [2000005];
void Ciur(){
IsPrime[0] = 0;
IsPrime[1] = 0;
for (int i=2;i<=1000000;++i){
IsPrime[i] = 1;
}
for (int i=2;i<=1000000;++i){
for (int j=2*i;j<=1000000;j+=i){
IsPrime[j] = 0;
}
}
}
int main()
{
Ciur();
int n;
fin >> n;
int Raspuns = 0;
for (int i=2;i<=n;++i){
if(IsPrime[i]==1){
Raspuns += 1;
}
}
fout << Raspuns;
return 0;
}