Cod sursa(job #524031)
Utilizator | Data | 19 ianuarie 2011 22:57:10 | |
---|---|---|---|
Problema | Ciurul lui Eratosthenes | Scor | 0 |
Compilator | cpp | Status | done |
Runda | Arhiva educationala | Marime | 0.25 kb |
#include<fstream.h>
ifstream fin("ciur.in");
ofstream fout("ciur.out");
int n,i,j,nr;
int ciurul(int x)
{ bool p[2000012];
for(i=2; i<=x; i++)
if(!p[i])
{ nr++; for(j=i+i; j<=x; j+=i) p[j]=1;}
return nr;
}
int main()
{ fin>>n; fout<<ciur(n)<<'\n';}