Cod sursa(job #2909794)
Utilizator | Data | 15 iunie 2022 20:39:02 | |
---|---|---|---|
Problema | Ciurul lui Eratosthenes | Scor | 100 |
Compilator | cpp-64 | Status | done |
Runda | Arhiva educationala | Marime | 0.39 kb |
#include <bits/stdc++.h>
#define N 2000005
using namespace std;
ifstream fin("ciur.in");
ofstream fout("ciur.out");
int main()
{
int n, cnt=0;
char ciur[N];
fin>>n;
for(int i=2; i<=n; i++)
ciur[i] = 1;
for(int i=2; i<=n; i++)
if(ciur[i]==1)
{
++cnt;
for(int j=i*2; j<=n+1; j=j+i)
ciur[j]=0;
}
fout<<cnt;
return 0;
}