Cod sursa(job #392653)
Utilizator | Data | 7 februarie 2010 23:17:12 | |
---|---|---|---|
Problema | Ciurul lui Eratosthenes | Scor | 10 |
Compilator | cpp | Status | done |
Runda | Arhiva educationala | Marime | 0.39 kb |
#include<iostream>
#include<fstream>
#include<stdio.h>
#include<vector>
using namespace std;
int *v=new int[2000005];
int main()
{int i,j,k,n;
ifstream fin("ciur.in");
fin>>n;
v[0]=v[1]=1;
k=1;
for(i=2;i<=n;i++)
{if(v[i]==0)
for(j=i*i;j<=n;j+=i)
{v[j]=1;
k++;}
}
freopen("ciur.out","w",stdout);
printf("%d \n",n-k);
return 0;
}