Cod sursa(job #2504626)
Utilizator | Data | 5 decembrie 2019 12:02:06 | |
---|---|---|---|
Problema | Ciurul lui Eratosthenes | Scor | 70 |
Compilator | cpp-64 | Status | done |
Runda | Arhiva educationala | Marime | 0.46 kb |
#include <iostream>
#include <fstream>
#include <cmath>
using namespace std;
int p[2000000];
ifstream f("ciur.in");
ofstream g("ciur.out");
int main()
{
int n,i,j,nr=0;
f>>n;
for(i=2;i<=sqrt(n);i++)
{
if(p[i]==0)
{
for(j=2*i;j<=n;j=j+i)
{
p[j]=1;
}
}
}
for(i=2;i<=n;i++)
{
if(p[i]==0)
{
nr++;
}
}
g<<nr;
return 0;
}