Cod sursa(job #1884031)
Utilizator | Data | 18 februarie 2017 13:42:21 | |
---|---|---|---|
Problema | Ciurul lui Eratosthenes | Scor | 30 |
Compilator | cpp | Status | done |
Runda | Arhiva educationala | Marime | 0.38 kb |
#include <fstream>
using namespace std;
ifstream f("ciur.in");
ofstream g("ciur.out");
int prim[2000000],ct;
int main()
{
int n;
f>>n;
for(int i=2;i<=n;i++)
prim[i]=1;
for(int i=2;i<=n;i++)
if(prim[i])
{
ct++;
for(int j=i+i;j<=n;j+=i)
prim[j]=0;
}
g<<ct;
return 0;
}