95 lines
2.1 KiB
Rust

/*
* Copyright (C) 2021 Ortega Froysa, Nicolás <nicolas@ortegas.org>
* Author: Ortega Froysa, Nicolás <nicolas@ortegas.org>
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
use structopt::StructOpt;
use std::path::PathBuf;
use std::fs::File;
use std::io::{BufRead, BufReader};
use std::collections::VecDeque;
#[derive(StructOpt)]
struct Opt {
#[structopt(short, long)]
verbose:bool,
#[structopt(short, long)]
import:Option<PathBuf>,
n:usize,
}
fn main() {
let opts = Opt::from_args();
// get the first `n` primes
let n = opts.n;
let mut primes:VecDeque<u64> = VecDeque::with_capacity(n);
let mut candidate:u64;
if opts.import.is_some()
{
let in_file = File::open(opts.import.unwrap()).unwrap();
let reader = BufReader::new(in_file);
for (index, line) in reader.lines().enumerate()
{
let line = line.unwrap();
let aux:u64 = line.parse().unwrap();
primes.push_back(aux);
}
candidate = *primes.back().unwrap() + 2;
}
else
{
// first prime
if opts.verbose
{
println!("{}", 2);
}
primes.push_back(2);
candidate = 3;
}
while primes.len() < n
{
let mut is_prime = true;
let limit = (candidate as f64).sqrt() as u64;
for i in primes.iter().take_while(|x| **x <= limit)
{
if candidate % *i == 0
{
is_prime = false;
break;
}
}
if is_prime
{
if opts.verbose
{
println!("{}", candidate);
}
primes.push_back(candidate);
}
candidate += 2;
}
if !opts.verbose
{
println!("{}", primes.get(n-1).unwrap());
}
}