Cod sursa(job #3175735)
Utilizator | Data | 26 noiembrie 2023 13:14:54 | |
---|---|---|---|
Problema | Ciurul lui Eratosthenes | Scor | 20 |
Compilator | c-64 | Status | done |
Runda | Arhiva educationala | Marime | 0.47 kb |
#include <stdio.h>
#include <stdbool.h>
#define MAXN 2000000
bool ciur[MAXN+1];
int sml[MAXN+1];
int prime = 0;
int main(){
for(int i=2; i*i<=MAXN; i++){
sml[i] = prime;
if(!ciur[i]){
prime++;
for(int d=i*i; d<=MAXN; d+=i)
ciur[d]=true;
}
}
int n;
FILE *fin, *fout;
fin = fopen("ciur.in", "r");
fscanf(fin, "%d", &n);
fclose(fin);
fout = fopen("ciur.out", "w");
fprintf(fout, "%d\n", sml[n]);
fclose(fout);
return 0;
}