Cod sursa(job #2380774)
Utilizator | Data | 15 martie 2019 14:57:08 | |
---|---|---|---|
Problema | Ciurul lui Eratosthenes | Scor | 100 |
Compilator | cpp-64 | Status | done |
Runda | Arhiva educationala | Marime | 0.45 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;
if(N>2)
S=1;
for(i=3; i<=N; i+=2)
{
if(v[i]==0)
{
S++;
for(j=i+i; j<=N; j+=i)
{
v[j]=1;
}
}
}
}
int main()
{
in>>N;
ciur();
out<<S;
return 0;
}