Cod sursa(job #1204979)
Utilizator | Data | 4 iulie 2014 16:17:05 | |
---|---|---|---|
Problema | Ciurul lui Eratosthenes | Scor | 30 |
Compilator | cpp | Status | done |
Runda | Arhiva educationala | Marime | 0.45 kb |
#include<fstream>
using namespace std;
#define MAXN 2000001
ifstream cin("ciur.in");
ofstream cout("ciur.out");
int A[MAXN],N;
int main() {
int i,j,k=0;
cin>>N;
for(i=1;i<=N;i++)
A[i]=i;
for(i=2;i<=N;i++){
if(A[i]!=0)
{
k++;
A[i]=0;
for(j=i*i;j<=N;j+=i)
A[j]=0;
}
}
cout<<k;
return 0;
}