Cod sursa(job #2467527)
Utilizator | Data | 4 octombrie 2019 16:20:02 | |
---|---|---|---|
Problema | Ciurul lui Eratosthenes | Scor | 0 |
Compilator | cpp-64 | Status | done |
Runda | Arhiva educationala | Marime | 0.34 kb |
#include <bits/stdc++.h>
using namespace std;
ifstream in ("ciur.in");
ofstream out ("ciur.out");
bool prim[2000000];
int main()
{ int x, i, n, cnt=0, j;
in>>n;
for(i=2; i*i<=n; i++)
prim[i]=1;
for(i=2; i*i<=n; i++)
if(prim[i]==1)
{
for(j=i*i; j<=n; j=j+i)
prim[i]=0;
}
if(prim[i]==1)
cnt++;
out<<cnt;
return 0;
}