Cod sursa(job #1284415)
Utilizator | Data | 6 decembrie 2014 15:18:46 | |
---|---|---|---|
Problema | Ciurul lui Eratosthenes | Scor | 100 |
Compilator | cpp | Status | done |
Runda | Arhiva educationala | Marime | 0.42 kb |
#include <fstream>
using namespace std;
ifstream in ("ciur.in");
ofstream out ("ciur.out");
int N, cnt;
char prim[2000005];
int main()
{
int i, j;
in>>N;
for (i = 2; i <= N; ++i)
prim[i] = 1;
for (i = 2; i <= N; ++i)
if (prim[i])
{
++cnt;
for (j = i+i; j <= N; j += i)
prim[j] = 0;
}
out<<cnt;
return 0;
}