Cod sursa(job #1996977)
Utilizator | Baboiu Razvan B_Razvan | Data | 3 iulie 2017 09:48:28 |
---|---|---|---|
Problema | Ciurul lui Eratosthenes | Scor | 100 |
Compilator | cpp | Status | done |
Runda | Arhiva educationala | Marime | 0.5 kb |
#include <iostream>
#include <cstdio>
#define NMAX 2000000
using namespace std;
int n;
char ciur[NMAX];
int nrElemCiur()
{
int nr = 0;
for(int i=2; i<=n; ++i)
{
if(ciur[i]==0)
{
nr++;
for(int j=i+i; j<=n; j+=i)
ciur[j]=1;
}
}
return nr;
}
int main()
{
freopen("ciur.in", "r", stdin);
freopen("ciur.out", "w", stdout);
scanf("%d", &n);
printf("%d", nrElemCiur());
return 0;
}