Cod sursa(job #2380770)
Utilizator | Data | 15 martie 2019 14:53:36 | |
---|---|---|---|
Problema | Ciurul lui Eratosthenes | Scor | 70 |
Compilator | cpp-64 | Status | done |
Runda | Arhiva educationala | Marime | 0.46 kb |
#include<bits/stdc++.h>
using namespace std;
ifstream in("ciur.in");
ofstream out("ciur.out");
bool v[2000001];
int N,S;
void ciur()
{
int i,j;
S=N;
for(i=3;i<=N;i+=2)
{
for(j=i+i;j<=N;j+=i)
{
v[j]=1;
}
}
for(i=2;i<=N;i+=i)
{
v[i]=1;
}
for(i=1;i<=N;i++)
{
S=S-v[i];
}
}
int main()
{
in>>N;
ciur();
out<<S;
return 0;
}