Inserisci in stdin la quantità di numeri in input e infine quali n-esimi numeri primi si vuole sapere

PrimeCached.rs

use std::io;
use std::fmt::Write;

/*
STDIN:
4
7 1 199999 4

STDOUT:
17 2 2750131 7
*/

fn main() {
    let mut buffer = String::new();
    io::stdin().read_line(&mut buffer);
    let q = buffer.trim().parse::<usize>().unwrap();
    buffer.clear();
    io::stdin().read_line(&mut buffer);
    let texts : Vec<&str> = buffer.split_whitespace().collect();
    let mut indexes: Vec<u32> = Vec::with_capacity(q);
    for t in texts.iter() {
        indexes.push(t.trim().parse::<u32>().unwrap());
    }
    let maxindex = *(indexes.iter().max().unwrap()) as usize;
    let mut primes: Vec<u32> = Vec::with_capacity(maxindex);
    primes.push(2);
    let mut p = 3;
    loop {
        let limit = (p as f32).sqrt() as u32;
        let mut isprime = true;
        for controlp in (&primes).iter() { 
            if p % controlp == 0 {
                isprime = false;
                break;
            }
            if controlp > &limit { break; }
        }
        if isprime == true {
            primes.push(p);
            if primes.len() >= maxindex {
                break;
            }
        }
        p += 2;
    }
    let mut result = String::new();
    for req in indexes.iter() {
        write!(&mut result, "{} ", primes[(req - 1) as usize]);
    }
    print!("{}", result.trim());
}