Cod sursa(job #2105839)
Utilizator | Data | 14 ianuarie 2018 13:42:45 | |
---|---|---|---|
Problema | Ciurul lui Eratosthenes | Scor | 100 |
Compilator | cpp | Status | done |
Runda | Arhiva educationala | Marime | 0.4 kb |
#include <iostream>
#include <fstream>
using namespace std;
ifstream in("ciur.in");
ofstream out("ciur.out");
bool prim[2000005];
int main()
{int i,n,j,cnt=0;
in>>n;
for (i = 2; i <= n; ++i)
prim[i] = 1;
for (i = 2; i <= n; ++i)
if (prim[i])
{
++cnt;
for (j = i+i; j <= n; j += i)
prim[j] = 0;
}
out<<cnt;
return 0;
}