Cod sursa(job #2514402)
Utilizator | Data | 25 decembrie 2019 17:27:32 | |
---|---|---|---|
Problema | Ciurul lui Eratosthenes | Scor | 100 |
Compilator | cpp-64 | Status | done |
Runda | Arhiva educationala | Marime | 0.49 kb |
#include <iostream>
#include <fstream>
#include <cmath>
using namespace std;
int main()
{
ifstream fin("ciur.in");
ofstream fout("ciur.out");
long long int N, i, j, nr;
char v[2000005];
fin>>N;
for(i=0;i<=N;i++)
v[i]=1;
nr=0;
v[0]=0;
v[1]=0;
for(i=2;i<=N;++i)
if(v[i]==1)
{
nr++;
for(j=i+i;j<=N;j=j+i)
v[j]=0;
}
fout<<nr;
return 0;
}