Cod sursa(job #2052222)
Utilizator | Data | 30 octombrie 2017 11:18:28 | |
---|---|---|---|
Problema | Ciurul lui Eratosthenes | Scor | 30 |
Compilator | cpp | Status | done |
Runda | Arhiva educationala | Marime | 0.29 kb |
#include <iostream>
#include <fstream>
using namespace std;
ifstream f("ciur.in");
ofstream g("ciur.out");
int n,i,j,a[2000001],nr=1;
int main()
{f>>n;
a[2]=1;
for (i=3;i<=n;i=i+2)
a[i]=1;
for (i=3;i<=n;i=i+2)
if (a[i]==1) {nr++;
for (j=3*i;j<=n;j=j+2*i)
a[j]=0;}
g<<nr;
}