Cod sursa(job #3232589)
Utilizator | Data | 31 mai 2024 06:28:19 | |
---|---|---|---|
Problema | Ciurul lui Eratosthenes | Scor | 100 |
Compilator | cpp-64 | Status | done |
Runda | Arhiva educationala | Marime | 0.27 kb |
#include<bits/stdc++.h>
using namespace std;
ifstream F("ciur.in");
ofstream G("ciur.out");
bitset<2000001> a;
int n,i,j;
int main()
{
for(F>>n,i=3;i*i<=n;i+=2)
if(!a[i])
for(j=i*i;j<=n;a[j]=1,j+=2*i);
return G<<(n+1)/2-a.count(),0;
}