Cod sursa(job #153376)
Utilizator | Diculescu Elena Alexandra portocala | Data | 10 martie 2008 14:57:42 |
---|---|---|---|
Problema | Ciurul lui Eratosthenes | Scor | 20 |
Compilator | cpp | Status | done |
Runda | Arhiva educationala | Marime | 0.42 kb |
#include<fstream.h>
#define dim 20000//01
char v[dim];
long n,nr;
void ciur()
{long i,j;
for(i=2;i<=n;i++)v[i]=1;
j=1;char ok=1;
while(ok)
{while(!v[j]&&(j<=n))j++;
if(j<=n)
{nr++;
for(i=j+1;i<=n;i++)
if(v[i])
if(!(i%j))v[i]=0;
j++;
}
else ok=0;
}
}
int main()
{ifstream f("ciur.in");
f>>n;
f.close();
ciur();
ofstream g("ciur.out");
g<<nr<<'\n';
g.close();
return 0;
}