Cod sursa(job #1988645)
Utilizator | Data | 3 iunie 2017 23:16:04 | |
---|---|---|---|
Problema | Ciurul lui Eratosthenes | Scor | 100 |
Compilator | cpp | Status | done |
Runda | Arhiva educationala | Marime | 0.45 kb |
#include <iostream>
#include <fstream>
using namespace std;
ifstream in("ciur.in");
ofstream out("ciur.out");
int main()
{
int N, cnt=0;
char prim[2000005];
int i, j;
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;
}