Cod sursa(job #385446)
Utilizator | Data | 22 ianuarie 2010 18:51:33 | |
---|---|---|---|
Problema | Ciurul lui Eratosthenes | Scor | 100 |
Compilator | cpp | Status | done |
Runda | Arhiva educationala | Marime | 0.35 kb |
#include <fstream.h>
ifstream f("ciur.in");
ofstream g("ciur.out");
int N,cnt;
char prim[2000005];
int main()
{
int i,j;
f>>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;
}
g<<cnt;
return 0;
}