Cod sursa(job #1381888)
Utilizator | Data | 8 martie 2015 13:30:36 | |
---|---|---|---|
Problema | Ciurul lui Eratosthenes | Scor | 100 |
Compilator | c | Status | done |
Runda | Arhiva educationala | Marime | 0.43 kb |
#include <stdio.h>
#include <stdlib.h>
int N, cnt;
char prim[2000005];
int main()
{
int i, j;
freopen("ciur.in", "r", stdin);
freopen("ciur.out", "w", stdout);
scanf("%d", &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;
}
printf("%d\n", cnt);
return 0;
}