Cod sursa(job #1988487)
| Utilizator | Data | 3 iunie 2017 10:15:47 | |
|---|---|---|---|
| Problema | Ciurul lui Eratosthenes | Scor | 0 |
| Compilator | cpp | Status | done |
| Runda | Arhiva educationala | Marime | 0.51 kb |
#include <bits/stdc++.h>
using namespace std;
ifstream fin("ciur.in");ofstream fout("ciur.out");
int main()
{ const int Nmax=1000001;
bitset<Nmax>ciur;
ciur[1]=1;
for(int i=4;i<=Nmax;i+=2)
ciur[i]=1;
for(int i=3;i*i<=Nmax;i+=2){
if(ciur[i]==0)
for(int j=i*i;j<=Nmax;j=j+2*i){
ciur[j]=1;
}
}
int n,a,cnt=0;
fin>>n;for(int i=0;i<n;i++){
fin>>a;if(ciur[a]==0)cnt++;
}
fout<<cnt;
return 0;
}
